Hi legendlink,
Depends on your download whether source is included.
You can get the source by downloading the latest change set from codeplex.
Oh, btw, welcome to umbraco.
Maybe it would be nice to tell what you're after. As umbraco is a complete 'framework' for building state-of-the-art (cms) websites, you don't actually need the source to run umbraco. In fact, it is advised to first have a look at how the system 'works'. Once you get to know the basics and want to go beyond, then it is defenitely a good idea to get the source and play with it.
You may find nice umbraco related tutorials and how-to's, although we're aware of the fact that documentation still lacks. Don't get disencouraged by that, just ask your questions in this forum. Lots of friendly people will answer any question.
Good luck on your journey.
Regards,
/Dirk
level 1 certified - umbraco blog at
netaddicts.be - working on an integrated forum4umbraco