Yep, I second that. SIO2PC is by far the most awesome thing you can get for your atari. especially on a dollar per functionality basis. Disk drives are a thing of the past.
The ability to load and save data directly to your PC as disk images, and then freely exchange these images with other users is awesome.
Not to mention the fact that you can have every atari game ever made at you instant disposal in a few hudred megs in a directory on your PC hardrive and just "drag & drop" them into place to instantly load and play them on your ATARI.
The program, APE (Written and maintained by Steve Tucker of
http://www.atarimax.com) is truly awesome, and uses your PC to emulate 8 disk drives, any modem configuration, and any printer or plotter configuration simultaneously.
Your atari "thinks" its got a huge stack of ATARI hardware hooked to it's SIO port. And it is actualy much faster than the "real thing"..
All you need is an SIO2PC cable which can be assembled for a few dollars worth of parts, or purchased directly from atarimax.com.