SlowGold slows down music without changing the pitch, so you can play along with every note. Learn the secrets of your favorite guitarists, directly from their recordings!
http://www.hitsquad.com/smm/programs/Slowgold/

Other software includes:

Amazing Slow Downer 1.07 for Windows 95/98/NT/2000/ME
http://www.hitsquad.com/smm/programs/AmazingSlowDowner/

Slow Me Down Winamp DSP Plug-in for Windows 95/98/2000/NT
http://www.hitsquad.com/smm/programs/SlowMeDown/

Slow Speed CD Transcriber for Windows 95/98/NT/2000
http://www.hitsquad.com/smm/programs/SlowSpeed/

Chronotron for Windows 95/98
http://www.hitsquad.com/smm/programs/Chronotron/

Slow Down Moses for Windows 95/98
http://www.hitsquad.com/smm/programs/Slow_Down_Moses/