The Springfield cluster is composed of 24 diskless dual-opteron 1U compute nodes, 1 login master node and 1 4U fileserver.
First you must get an account on the cluster from the system administrator. Once you have an account you can access the cluster thru ssh. If you are using Macintosh OS X you can use the teminal program. Linux users can use ssh from the command line, and Windows users can use putty. To run programs on the cluster, which requires to open a window (e.g. emacs) you must login with the -Y option ssh (ssh -Y springfield.physics.ucla.edu). Your computer must also support the Linux window management, which is native on Linux machines. For MacOS X use X11 and Cygwin for Windows.
For file transfer you can use either scp or sftp. MacOS X and Linux can use the command line scp program. For MacOS X fugu is an available GUI for sftp. Winscp and filezilla are free and easy to use guis for Windows.