I know ASP and ASP.NET are COMPLETELY different? But what's similar? Is it worth learning? Where should I start?

I'm treating the whole .NET thing as being a completely new language but I'm beginning to think that's even too narrow... is each .NET initiative a new language base unto itself?

I guess I need a quick rundown of what .NET is, and what I as an ASP'er and Lead Developer should be focusing on in my learning.