browser integration in C#

You need to write shell extension.
Here are the docs on the subj
*msdn.microsoft.com/msdnmag/issues/04/01/WindowsShell/
*www.kbcafe.com/juice/?guid=20041022155459


but if u want it simple
for simple extensions like this you only really have to
add a few registry entries. It's described at

*msdn.microsoft.com/library/en-us/s...ell_basics/shell_basics_extending/context.asp

And you shouldn't be writing shell extensions in managed code anyway.