One of the best SCSI controller cards I've used is the Fastlane Z3. Supports Zorro 3 DMA SCSI, plus the addition of fast memory (32 bit access), providing you can find 30 pin SIMMs. :-)
Unfortunately these cards are quite rare and expensive.
You can get those IDE to SCSI converting things. Haven't used them before though. They're possibly a bit pricey.
If you want to back some stuff up to a 2nd computer with a minimal cost, either use a cheap P2P network, like some form of parallel or serial soloution. Slow and nasty, but works OK if you've got the time.
Another option is just buy a new IDE hard drive. Even 20Gb drives are almost giveaway items now.
Format it with a decent file system like PFS3-DS so you won't have disk size problems.
Add it to your internal IDE controller and copy your stuff accross.
