Is there a Visual Basic 6 decompiler?

http://www.program-transformation.org/Transform/VisualBasicDecompilers

This link provides a lot of resources for VB6 Decompiling, but it seems like it will depend greatly on what you DO have (do you still have the pre-link Object code [EDIT: er... p-code I mean], or just the EXE?) Either way, it looks like there's something, take a look in there.

For the final, compiled code of your application, the short answer is “no”. Different tools are able to extract different information from the code (e.g. the forms setups) and there are P code decompilers (see Edgar's excellent link for such tools). However, up to this day, there is no decompiler for native code. I'm not aware of anything similar for other high-level languages either.

I have used VB Decompiler Lite (http://www.vb-decompiler.org/) in the past, and although it does not give you the original source code, it does give you a lot of information such as method names, some variable strings, etc. With more knowledge (or with the full version) it might be possible to get even more than this.