Sometimes things get a bit frustruating, recently we had to setup a standard Active / Passive (though they, Micro$oft, call it something different now) cluster. The new thing here for us was it is SQL 2008 on Windows 2008 R2.
So maybe these two little items will help you avoid some issues...
1. Slip Stream Service pack 1 before installing.
I don't remember the exact error, but the solution to the problem is to slip stream service pack 1 into the sql server media before installing the cluster.
2. Uncheck the DHCP option and put in the Virtual IP Address.
Also be aware the Windows 2008 is just a bit quirky at first, the new UAC (User Access Controls) take a bit too get used to, as well as right clicking on your executables and selecting "Run as Administrator", even though you are logged in as an administrator.
My other favorite Windows 2008 message is when you are browsing a folder structure in Exploder (err... I mean Explorer) and the OS throws up a prompt about "Not having permissions, would you like to continue anyway ?".... How the f*** can you not have permissions, but than continue anyway ? Stupid Computer !
Anyway, lots of good information on how UAC Protects you from yourself (sounds very much like a Democrat !); read up on it: http://technet.microsoft.com/en-us/library/dd446675%28WS.10%29.aspx