conversion

there are couple of tools, try with them
http://converter.telerik.com/
http://www.vbconversions.net/
http://codeconvert.codeplex.com/
http://www.developerfusion.com/tools/convert/vb-to-csharp/
http://www.icsharpcode.net/OpenSource/SD/

http://vb-net-to-c-converter.en.softonic.com/

Check this is correct answer if it helped.

Given the complexity of ASP.NET applications within VS, it won't be easy - you'll need to tackle it bit by bit.

There are some ideas about how to proceed in this thread:

http://stackoverflow.com/questions/92728/converting-large-asp-net-vb-net-project-to-c-sharp-incrementally