I am fresh out of college (passed in 07) and have been working on a Windows Forms project since then.
I have a decent understanding of C# (not all the features of the language only the ones that i got to use in the project) and am very interested in learning ASP .NET
Would it be better to start learning ASP .NET and pick up C# as i go along or do i first master the language and then start with ASP .NET
EDIT: I am talking about the 3.5 version of the .NET framework
You're conflating some terminology. C# is a language. ASP.NET is a way to use a language (typically, C# or VB.NET) to create web-pages. So if your two interests are C# and ASP.NET....
Do ASP.NET in C#.
I was a straight VB6 developer when I started transitioning to VB.Net. I'd only done desktop applications - not a single thing in the web world. I started learning ASP.Net (job required it) and decided, at the same time, to switch to C#.
Re-did a couple of small applications that I'd previously written in VB6 and VB.Net in C# and just went on from there.
You can quite easily pickup C# and ASP.Net at the same time. You might want to consider learning ASP.Net MVC, as well as/instead of "normal" ASP.Net.
You should be fine to learn C# while working on an ASP.NET project. I will advise that if you're already pretty familiar with the Web, you'll probably find working with the ASP.NET MVC framework more enjoyable. ASP.NET takes some liberties with the page lifecycle in an attempt to make web pages programmed more like desktop applications. Personally, I think this makes ASP.NET hard to use, but then my background is in Perl and PHP.
When I learned asp.net and C# I learned them at the same time but separately. I got a good book about ASP.net with C# and I also got a book just about C#. I found that helped. It sounds like you already use C# so it shouldn't be a problem for you.
As others mentioned, another thing to consider is asp.net webforms vs asp.net MVC. If your background is winforms then webforms will make sense. If your background is php or a non event driven framework then MVC will probably make more sense.
MVC is the 'hot' new thing everyone is talking about with asp.net these days. However, realistically there are a lot more resources, tutorials and code samples for webforms. I'm sure that will change as MVC comes out of beta and gets used more.
As far as I'm concerned, the only true way to learn is by doing. Hit the official ASP.Net site and download the tutorials and working through them.
Remember ASP.Net is NOT a language but a way of hooking up HTML to your C#/VB.Net code. Have fun!
Since you already have some experience in C#, I would recommend that you dive right into an ASP.NET project. ASP.NET will present learning opportunities on the web side of things although webforms abstracts out much (maybe too much) of how the web works. Moving from winforms to webforms will help you be able to just jump right in but you will eventually want to look into MVC or another web framework (maybe PHP or even classic ASP).
I agree with most of the people here: Learn ASP.NET and C# at the same time. You'll have to - your code-behinds will be either VB.NET or C# anyway. Also check out MVC, and LINQ.
But, and here's the big thing, learn standards compliant HTML too! Most of the drag and drop controls in visual studio do horrible horrible things to HTML (gridview, I'm looking at you). If you follow proper HTML standards you'll also use learn what controls are more useful (repeater) than others when developing clean websites.