Character Sheets (printable):
Two Page Character Record Sheet

source: http://www.shadowrunrpg.com/resources/

4th Edition Character Generator:
SR4 CGE -- Windows only

This is the best character generator I could find. Quick install and very easy to use.

source: http://www.shadowrunrpg.com/resources/faq.shtml

3rd Edition to 4th Edition Conversion Guide:
SR3 to SR4 Character Conversion Guide [PDF]

source: http://www.shadowrunrpg.com/resources/

If you're wondering how the game mechanics work, please take a look at these cheat sheets. It looks like they cover all of the more complicated actions in the game.
Full Set of Cheat Sheets [PDF] - click here

source: http://www.pavao.org/shadowrun/index.html