Simon,
No problem. I've been going through the learning curve for the last 2 years, so I know what it's like.
As far as which language, my 'personal' preference is C#, because I worked in C and C++ for years. One of the great 'pioneers' from the days of Borland, Anders Helsberg (hope I spelled his name right) was a big architect for C#. Here are some things to keep in mind:
1) You'll hear from many people that the beef of .NET is in the framework classes, and so the language itself is a somewhat marginal decision.
2) There's an increasingly popular approach to using VB.NET for the user interface modules, and C# for the application (middle) tier.
3) Some are of the opinion that MS may 'promote' VB.NET more and more in future versions of .NET.
4) If you've used VB or C/C++ in the past, that may help with which one you might feel more productive in. If you've never worked much in either one, I can't really say which will be more suited for you.
A few weeks ago, Cathi Gero posted a response on languages, which included a web site reference on language differences. I'll see if I can dig it up.
Kevin