I've got the basic tool completed now and it works in game (well there's no crashes - is there any other way to check this? Maybe the news items about retired HoF inductees?) and works fine with the Pre Game Editor. I'm now going to work on the additional features to make the league selection customisable and so it can be used across different databases.
I really want to try and get it released this weekend so that users can try it out on the Manimal v4.1 Rosters (they will be able to download my tool, load it and then play the game). However, I really need somebody with better knowledge of the North American leagues than I to check I've got the correct ones listed. If anyone could take a look at the lists below then I'd be really very grateful. 
 
I've just copied and pasted these straight from my programming code, and so just ignore the numbers listed (just pay attention to the league names):
Canadian Juniors wrote:6,		// Western Hockey League (WHL)
			7,		// Ontario Hockey League (OHL)
			8,		// Quebec Major Junior Hockey League (QMJHL)
			33,		// Memorial Cup
			120,	// Alberta Junior Hockey League (AJHL)
			121,	// British Columbia Hockey League (BCHL)
			124,	// Ontario Provincial Junior A Hockey League (OPJHL)
			126,	// Saskatchewan Junior Hockey League (SJHL)
			283,	// Maritime Junior A Hockey League (MJAHL)
			284,	// Manitoba Junior Hockey League (MJHL)
			285,	// Quebec Junior AAA Hockey League (QJAHL)
			302,	// Northern Ontario Junior Hockey League (NOJHL)
			311,	// Superior International Junior Hockey League (SIJHL)
			581		// Ontario Junior A Hockey League (OJAHL)
North American Major Juniors wrote:119,	// United States Hockey League (USHL)
			123,	// North American Hockey League (NAHL)
			331,	// North American Hockey League North
			332,	// North American Hockey League South
			333,	// North American Hockey League West
			515,	// North American Hockey League Midwest
			544,	// North American Hockey League Central
			545,	// United States Hockey League Eastern Conference
			546		// United States Hockey League Western Conference
North American Juniors wrote://?		// Atlantic Junior Hockey League (AJHL)
			//?		// Eastern States Hockey League (ESHL)
			//?		// Great Lakes Junior Hockey League			
			122,	// Eastern Junior Hockey League (EJHL)			
			325,	// Southeast Hockey League
			330,	// America West Hockey League (AWHL)
			341,	// Central States Hockey League (CSHL)
			342,	// Empire Junior B Hockey League
			343,	// Empire Jr. B Hockey League West
			344,	// Empire Jr. B Hockey League East
			345,	// Minnesota Junior Hockey League (MJHL)
			346,	// Metropolitan Junior Hockey League
			407,	// Western States Hockey League (WSHL)
			410		// Northern Pacific Hockey League (NPHL)
North American College Leagues wrote:12,		// Hockey East (HE)
			21,		// Central Collegiate Hockey Association (CCHA)
			22,		// Eastern Collegiate Athletic Conference (ECAC)
			23,		// Western Collegiate Hockey Association (WCHA)
			29,		// National Collegiate Athletic Association (NCAA)
			132,	// Metro Atlantic Athletic Conference (MAAC)
			133,	// College Hockey America (CHA)
			334,	// Atlantic Hockey Association
			335,	// ECAC East
			336,	// ECAC West
			337,	// N.E. Small College Athletic Conference
			338,	// ECAC Northeast
			339,	// Northern Collegiate Hockey Association
			340,	// SUNY Athletic Conference
			347,	// Midwest Collegiate Hockey Association
			348,	// Minnesota Intercollegiate Athletic Conference
			547,	// Big 10 Conference
			548,	// Massachusetts State Collegiate Athletic Conference
			549		// Northeast-10 Conference
Professional leagues wrote:0,		// NA_: National Hockey League
			1,		// FIN: SM-League
			3,		// SWE: Elitserien
			4,		// NA_: American Hockey League
			5,		// NA_: East Coast Hockey League
			9,		// RUS: Superleague / KHL
			10,		// GER: Deutsche Eishockey Liga
			11,		// CZE: Elite League
			13,		// GBR: British Sekonda Ice Hockey Superleague
			14,		// SWI: National League A
			15,		// AUT: Erste Bank Eishockey Liga
			17,		// NA_: United Hockey League
			19,		// SVK: Slovenska T-Com Extraliga
			20,		// SWE: Swedish Allsvenskan
			24,		// NA_: Central Hockey League
			25,		// NA_: West Coast Hockey League
			26,		// SLO: Slovenian Elite League
			28,		// GBR: British National League
			30,		// DEN: Danish Oddset Ligaen
			31,		// NOR: Norwegian UPC-Ligaen
			48,		// NA_: International Hockey League
			49,		// NA_: World Hockey Association
			65,		// GBR: Elite Ice Hockey League
			73,		// NA_: ECHL West Division
			74,		// NA_: ECHL East Division
			75,		// NA_: ECHL South Division
			76,		// NA_: ECHL North Division
			84,		// NA_: ECHL American Conference
			85,		// NA_: ECHL National Conference
			91,		// RUS: Russian Vysshaya Liga
			95,		// ITA: Italian Serie A
			97,		// GER: Deutsche 2. Bundesliga
			98,		// GER: Deutsche Oberliga
			101,	// SWI: Swiss National League B
			102,	// CZE: Czech First Division
			103,	// AUT: Austrian Nationalliga
			109,	// NOR: Norwegian First Division
			110,	// NOR: Norwegian Second Division
			111,	// RUS: Russian Vtoraya Liga
			113,	// SVK: Slovakian First Division
			118,	// BLR: Belarus Hockey League
			129,	// NA_: Ligue Nord-Américaine du Hockey
			130,	// NA_: Atlantic Coast Hockey League
			134,	// DEN: Danish Cup
			141,	// GBR: British Challenge Cup
			145,	// JAP: Japanese Ice Hockey League
			167,	// GBR: English Premier Ice Hockey League
			209,	// CZE: Czech Second League
			282,	// NA_: Western Professional Hockey League
			287,	// NED: Dutch Superleague
			327,	// NA_: Southern Professional Hockey League
			455,	// CAN: Quebec Senior Professional League
			513,	// CAN: North East Professional Hockey League
			527		// NA_: Federal Hockey League
The way I have written the code, it is not possible for a league to fall within more than one of the following four categories listed below. Will this cause a problem (I can easily change the code so leagues can fall under more than one category)?
1) North American Major Juniors
2) North American Juniors
3) North American College
4) Canadian Juniors