MIT Secure is the preferred wireless network for members of the MIT community. You can use your Athena username and password to connect. IS&T has provided a web page with connection instructions for different clients.
MIT Guest may be used by visitors. It is unencrypted and has limited access to MIT resources.
Eduroam is another option for MIT community members and visitors from other schools. It can be quite slow though, so MIT Secure is still preferred for those with MIT accounts.
The IS&T Knowledgebase has more information about wireless networks on campus.
If you would like a wired network connection, you would need to either register for DHCP service (for a dynamically assigned address), or request a hostname (for a statically assigned address). Then plug in to one of the green network ports in your office. Once again, the Knowledgebase has more information.