That might be a tough one. I had no problems compiling the kernel, the problem was getting it to work. The win4lin module would always oops on me as soon as it got loaded. I was using the lastest mki-adapter patch and the "pristine" 2.6.10 patch from Netraverse's website.
I tried it with the 766 FC3 kernel. There was a slight patch mismatch with stock 2.6.10 Win4Lin patches. Easy to fix, though. Though, It oopsed on module load. Then I removed the -ac patch and retried. Same thing -- oops. Then removed couple other patches that seemed related to vm and friends. Same thing.
Didn't try it yet with a barebone 2.6.10 kernel, but so far for me it looks like Win4Lin simply doesn't work on 2.6.x kernels
That machine otherwise works fine, and just out of paranoia a memcheck86 run and mersenne.org stress tests passed after running each for 24 hours.
Needless to say, FC3 doesn't like too much when you start it up on a 2.4.x kernel. Hotplug doesn't work, at least (duh, it's 2.4!). So I wouldn't recommend running it with 2.4 for most people. If someone could be kind enough to nail down exactly which patches from a recent 2.6.x FC3 kernel play ball with win4lin patches, it'd help all of us immensely.