DrScheme (from Rice University) is a very complete implementation of Scheme, along with a rich set of debugging tools and extensions. See the DrScheme home page at Rice for more info.
All of the ports of DrScheme look and act the same. You will need to install and configure it for the platform you will use. The simplest way to use DrScheme at UW is to use the version already installed and configured for departmental Linux machines.
No matter which version you choose you will need to select the correct version of the Scheme language. You should be prompted for it the first time you run drscheme, but you can always set it by selecting the Languages menu and choosing Textual(MzScheme, includes R5RS) under the PLT bullet (which you may have to expand) under the Professional Languages bullet. Your language choice will be shown on the second line of the bottom window of DrScheme.
You can use DrScheme by typing "drscheme" at the command prompt.
If you want to use DrScheme on a different platform, you will have to download your own copy and install it. All of the ports of DrScheme work identically, so the programs and the results will be the same no matter where you run DrScheme. To download DrScheme, go to http://drscheme.org/.
Updated Sat October 16 10:56:11 CST 2004