I bought a computer on e-bay for about 40 dollars. It is a Pentium 3 with a cdrom only. I have a monitor, keyboard, and mouse thats left over from a computer that died.
My question is the cd downloads, all 31 of them. Are they the same as torrent downloads ( are they interchangeable).
The reason I ask is I started the download with bit torrent and did 4 cd's. Then
switched to just the straight download of the cd's. Dose any body know if
I need change the first 4 or are they interchangeable.

What "downloads" are you talking about exactly? Are you talking about the install disks that most distributions provide? What distro?

If so, then yes, the bittorrent versions are likely exactly the same as the direct download versions. Bittorent is just a distribution system that many distros use to help take pressure off their servers. If the filename is the same, then it's likely the same file. (Although you should always verify the md5 checksums to ensure that they're identical.)

But as for "31 disks", again, if you're talking about an installation cd, then you likely don't need to download them all. The first disk usually contains the installer and all the files necessary to get the basic system up and running, and the remaining disks are generally stores of all the software packages provided by the distro, 99% of which you'll never need. Not to mention that once you get your system running you can generally install them directly from the net anyway.

Extra disks can also be versions of the distro for other cpu architectures, like alpha and powerpc, or other specialized setups, so be sure you're getting the one suited for your system (that would be the x86 version for PIII).