I used some fMRI software awhile back, but it was on a Silicon Graphics system running Solaris. I have a feeling that most of it is UNIX-based, so binaries probably won't work. You MIGHT be able to compile the source code after tweaking it a bit. You might also want to check out www.freshmeat.net
they have a limited amount of MRI visualization software that runs on linux natively. I noticed that if you register first and then do a search for MRI, you get one app (J-slice or something), then click on the "Medical/Science Apps" filter, you'll get a couple more hits.