pofadda,
These should work OK: Mandriva 2007.1, Ubuntu 6.10 (liveCD), Fedora Core 6, PCLinuxOS 2007, Sabayon 3.3, Debian Etch (latest isos), Slackware 11 (if you select the 2.6 kernel)
And those had to be stubborn again
: Suse 10.2, Mepis 6.5
Don't know what's with those Mepis guys... They've been having that jmicron option on the boot menu at least since RC2 and still it's not working. Rub it in some more. I even posted on their forum about RC2 to point out the problem; they suggested I install 32 bit instead ...
Anyway, as you can see, there are quite a number of distros that do handle the Jmicron alright - all of them 2.6.18 (Mandriva even has only 2.6.17 - a patched version, however). I understand there is also - somewhere, God knows where - a hidden option in the Suse installer that does enable the Jmicron controller - it doesn't appear to work for everyone, though.
And yes, the SATA DVD should help. Personally, I bought a PCI IDE controller card last year and that works too.