This has to be one of the most useful features I never new about (until about 4 weeks ago).

C:\Documents and Settings\kmoore\Desktop>pushd \\server\userfiles\kmoore

Z:\kmoore>copy myfile.txt d:
1 file(s) copied.

Z:\kmoore>popd

C:\Documents and Settings\kmoore\Desktop>dir /b
myfile.text

This works with local drives, too. So if you working in My Documents and you want to check something in %windir% you can just pushd %windr%, check things out, then popd. Pretty cool.