I wrote an open source SSIS decompiler that can deconstruct your package and replicate it in roughly equivalent C# code. I'd love to hear your feedback if this tool works for you.

http://code.google.com/p/csharp-dessist/downloads/list

I think specifically you'll find it useful because the program can extract all the SQL code from your package into individual statements; you can then easily see where each table is used.