MS programmers contributing to open-source?

From: Frederick Leslie Evans (fle_at_no-thankyou.com)
Date: 12/21/03 

Date: 21 Dec 2003 22:25:58 GMT

Hello, just a quick question: are employees of Microsoft forbidden by
contract from contributing to Linux and/or other free-software projects in
their leisure time? If so, is such a contractual term considered
controversial by programmers? If it is not actually prohibited, are MS
programmers nevertheless discouraged somehow from the practice as it
favours the competition, and do they have to contribute secretly if they
want to contribute at all? Lastly, *do* any of them make valuable
contributions to the free-software movement, overtly or covertly?

Thank you for any answers to these questions --Les