@Winterclaw - While 2.49b is the latest OFFICIAL release of Blender, the future of Blender lies with the 2.5X line.  The current beta, 2.56a is quite stable, but you will occassionally come across somethings that aren't quite solid.  I have both installed on my system, but am using 2.56a Beta almost exclusively.  To add more to that argument, there will be a line of books coming out very soon (one is already out) that focus exclusively on the 2.5X/2.6 Blender interface.

Most of the tuts at BlenderCookie are focused on the 2.5X/2.6 interface.  You can find OLDER tuts that are using the 2.49b, but you have to go back a ways.

 

Hope this helps!