hey, i'm considering taking on a theming/skinning project using Umbraco. how much ASP.NET will I need to know? I'm not familiar at all with ASP - but I have light-moderate experience with PHP (enough to get my hands pretty dirty with modifications inside a Druapl environment). My skill-set is primarily front-end (UX/UI, design, xhtml, css)

Just starting to check out the Umbraco site now, and at first glance they seem to have quite a few resources for learning it. Again, just wanted to see what any of you have to say about it, and what sort of learning curve should I expect?