Pretty much any half-height 5.25" drive will fit.
You could look at any of the bigger webtailers like PCConnection, Zones.com, Amazon, Outpost, Buy.com, or even office supply stores like Staples and OfficeMax.
The best places are probably the smaller, PC hobbyist places like NewEgg.com, MWave.com, googlegear.com, etc.
</a> has ongoing links to Hot Deals where you can possibly find great deals like $30 Memorex badged Lite-On 48/24/48x CD-RW drives at Staples (allegedly firmware hackable to 52x.)
You might want to compare model numbers of the internal mechanisms. I know the Memorex drive I mentioned above is a LTR-48246S.
[ 12-31-2002: Message edited by: Eugene ]</p>