w3schools is your friend
IMHO the learning curve is more than significant, but if you're up to date with your OOP then you'll be alright. In fact, if you are decent with good ol' programming, then ASP .NET will eventually make your life easier.
I started out with .NET, so I wouldn't know what it's like to come from LAMP, but there are a lot of people here at work that started out with regular ASP. Most of them make the mistake of scripting too much like they used to on regular ASP. In ASP .NET you want to keep the scripting to the minimum as most of the code will be separated from the HTML. Focus on this code separation paradigm when learning ASP .NET.
Your knowledge of VB6 will definately be of use as VB .NET is very similar, but if you have the time/will to do so, I recommend that you learn C# (although theoretically both languages yield the same results).
If you know oracle I don't think you'll have much trouble with sql server. You could start out with MS's
data application block, although you shouldn't use them for anything other than learning purposes.
A copy of Visual Studio .NET would be very helpful(although I hear it isn't cheap
).