There are beta versions available- for those that pay for the advanced developers kit.
there are also illegal versions out there, but I don't think anyone here is going to recommend them because A) it's illegal, and B) against forum policy.
just wait a couple more weeks and get the legitimate copy when it's released at WWDC.
i'm using the 2.0 firmware (and yes I'm an official developer I paid my $99). The most recent version is really nice but unless you are doing development for the 2.0 firmware or really want exchange push email it's probably not worth trying it yet. There are still some bugs.