I read about this and also some people on IRC said they can confirm it works too!!
The Euro PSP comes with 1.52fw and a 2.0fw upgrade disc so I put in the disc and started the upgrade, and at the point where it said "make sure the PSP is plugged into an AC adaptor" (do not plug it in before this point) is the last point at which you can cancel the upgrade. Anyway, before I continued I removed the disc and inserted the Midnight Club 3 (US Version with v1.50fw, as the Euro has v1.52fw on it) disc and then continued. Being that it had already bypassed the version check it continued to load the firmware thinking that it was the 2.0. Now I know that this works because I tried it on three of my friends PSPs all 1.51 I tried it on mine first so I wouldn't damage theirs.. and all of us can run homebrew now! I am guessing that this will only work on 1.5x versions seeing as how you can't use the 2.0 disc to upgrade one with 2.0 already on it.
Good luck to anyone who wants to try it! (risk your PSP, but others say it works fine so up to you)