When MVC first came out, I was reading about it everyday and learning all I could about it. About the time MVC 2 RC2 came out, I stopped learning for various reasons (new ho
Read and try "Nerd Dinner". I used it when I first started doing ASP.NET MVC2 2 months ago, and it helped a lot. (Right click the link and Save Target As. It's a PDF by Wrox)
Microsoft has a good page on ASP.NET MVC 2, which has tutorials covering most important aspects of the framework, as well as several references to blog posts going into things in more detail. That would seem a pretty natural place to start.
For MVC 3 the best resource currently seems to be Scott Gu's introductory blog post.
You can always hit the ASP.NET MVC site
http://www.asp.net/mvc
I dunno about you but I do better just looking at and writing code to figure things out. Jon Galloway has put up the MVC Music Store, I believe this has been updated for MVC 2
http://mvcmusicstore.codeplex.com/
Also the Nerd Dinner code has been updated for MVC 2 as well
http://nerddinner.codeplex.com/releases/view/45647
Finally Phil Haack has the updates to MVC 2 on his blog which has a number of links to tell you what has changed from 1 to 2. This post is probably the most valuable information if you just want to know what has changed from 1 to 2.
http://haacked.com/archive/2010/03/11/aspnet-mvc2-released.aspx
As the last couple of posters mentioned, Scott Gu has a good post on MVC 3 Preview 1 Features, and Phil Haack also has a post on his blog.
http://haacked.com/archive/2010/07/27/aspnetmvc3-preview1-released.aspx
Pick up the book "MVC2 in Action" from Manning and take a look at the latest MVCConf videos. I found the one done by Jimmy Bogard enlightening.