You should strongly consider using either Subversion or CVS to perform source code control for your project and the paper you write describing it.
I also strongly suggest writing your course project report using LaTeX. It is the de-facto tool in which most CS research papers are written. While it has a bit of start up cost, it's much easier to collaboratively write complex research papers using LaTeX than using word.
The most popular network simulators are ns-2 and Opnet. ns-2 is free, and CSD has some licenses for Opnet.
Emulab is a network emulation environment at the University of Utah. It provides racks of machines and programmable switches that can be configured to form mostly-arbitrary network topologies, with controllable delay and loss between nodes. It's a great way to test real programs in repeatable conditions or at scales that you can't get on your own.
Emulab also provides a set of wireless nodes that you can control, located around their building. They also have an experimental mobile robot testbed that could make for fun projects (the robots are designed to move computers and radios around so that you can do repeatable experiments involving mobility).
You must sign up to use a PlanetLab account. Please only sign up if you're going to use the account, since it imposes some management overhead on people not involved with the course.
Dave and some of the other faculty have a handful of various wireless nodes, cards, old laptops, etc., available that you may be able to use for your projects.
moteLab is a wireless sensor network deployed in the CS building at Harvard. It has 30 sensor motes that users can upload system images to, collect data from, etc. To use moteLab, you'll need to send them an email (listed on their web page). Please CC: dga on the mail.
Mistlab is a wireless testbed with 60 Mica2/Cricket nodes (sensor boards, much like the motes in moteLab) distributed over the 9th floor in the Stata center at MIT's Computer Science and AI Lab. For access, see their web page and send them an email, and please CC: dga on the mail.
Other potential resources: