Try Atomiq:
Atomiq Code Similarity Finder is a tool for developers to find and eliminate duplicate code. It is designed for .NET developers, but works equally well for developers of other languages and even web designers!
Atomiq works with a wide variety of source code:
We currently support C#, VB.Net, ASPX, Ruby, Python, Java, C, C++,
ActionScript, and XAML, with more extensions on the way soon. It is
the perfect companion tool for someone who updates their code
infrequently and can't possibly remember everything in it or for a
team of 2 or more developers working on the same project that don't
know everything in it since they didn't write it all themselves.
Eliminate similar code
(and the banging your head against the wall that comes with it) Atomiq
doesn't just find exact matches, it finds similar code. It ignores
"fluff" like whitespace, string content, curly braces, comments and
using/import statements so you can find the duplicate code that causes
problems. In VB.NET, it will also ignore lines that contain only
"Next", "End While", "End Try", "End If", "End Property", "End Get"
and "End Set".