If they just want to see VB.NET and C# source, and you don't tend to mix those (and VC++) in the same project, it wouldn't hurt to try the free Visual Studio 2008 Express Suite with your Java developers.
The Visual 2008 Express editions are available for free download. I recommend downloading the full DVD image and having the full set. These are my personal favorite tools for building portable code in interoperability projects.
Comparing Features of Visual Studio Editions
For those who want to verify what features are provided in the different editions of Visual Studio 2008, there is an extensive comparison table at the Visual Studio 2008 Product Comparison page.
If, as part of working with developers who are working on earlier versions, a Visual Studio 2008 Product Comparison is also currently available.
Alternative Editors and IDEs
There is an important benefit to using a Visual Studio 2008 edition, including an Express Edition, for reviewing .NET code of some software being inspected: built-in access to MSDN Library information and platform API descriptions, both locally and on-line. The on-line search finds reference materials and specifications on the MSDN site as well as on other sites that provide resources for developers using the Windows platform. (The MSDN library is also available separately for independent off-line use.)
For simpler inspection of .NET source programs, some of the programmer editors like Notepad++, jEdit, and others provide for syntax highlighting and formatting that works with .NET languages. There are also third-party IDEs that work with the .NET languages, including Sharpdevelop and Monodevelop.
Detailed Interoperability and Portability/Migration among Programming Language Tools
There are changes in compilers and level of programming-language implementation between the Visual Studio editions. Users of Visual Studio 6.0 will find that there are significant differences along with the addition of the .NET languages. In particular, the default conformance to the latest ISO standards and Unicode usage may be surprising for users of older VC++ versions, older C/C++ compilers from other sources, and older C/C++ textbooks and sample code.
For more information on changes in language and library features, consult the individual Developer Tools & Language selections of the main MSDN page.
The MSDN Forums on specific languages and products are a valuable way to obtain peer support. These forums (and web searches for other developer-support sites) are good resources for specific integration, library usage, and inter-product/platform code portability issues. Start with the closest-match to the Microsoft developer product you are working with and check with other developers on that forum.