Of Course! There are backwards compatible on the network.
Microsoft does have an official Windows 7 Support Forum located here http://tinyurl.com/9fhdl5 . It is supported by product specialists as well as engineers and support teams. You may want to check the threads available there for additional assitance and support.
Microsoft Windows Client Support
For leighjor's question and application, there are no issues to keep you from doing as he is doing. I run several Win7 X64 systems with a Win2003 server everyday with zero problems. Let be be sure I am clear.....zero.