Hi Juliano,
To work with mojoPortal you need the Web Application Project type which was originally not included in VS 2005, but was a separate installation. Recently they released SP1 for VS 2005 which includes the Web Application Project type.
I installed SP1 recently and now my version is 8.0.50727.762 (SP .050727-7600) and in the section "Installed Products" I have: Microsoft Web Application Projects 2005 77626-009-0000007-41878
So the answer is mojoPortal can be developed with any version of VS 2005 as long as you have the Web Application Project type, but today the best way to get this project type is to install SP1 for VS 2005
http://msdn.microsoft.com/vstudio/support/vs2005sp1/default.aspx
Hope it helps,
Joe