It depends how much you want to do, but if it is burning the odd cd you can google free burn software and get quite a few. If you want something a bit more solid and useable I would suggest taking a look at Nero. I used the full version of Nero with XP pro, but now use Nero 8 which came with my version of Windows 7 pro. No problems burning cd or dvd with either.
Edit. Here is a free Nero download you can get:
http://nero.windownloads.net/?OVRAW=...ID=25424940419