Visual Studio comes with a VCVARS32
(it might be renamed by now) batch file in its directory that will set all of these environment variables for you, and give you a shell with them set. It has a start menu entry, if you installed normally -- or maybe it came with the Platform SDK? It's been a while.
From the Microsoft documentation on the subject:
To run vcvars32.bat
At the command prompt, change to the \bin subdirectory of your Visual C++ installation.
Run vcvars32.bat by typing VCVARS32
.
Barring that, you can permanently set your environment variables (per-system or per-user) in Control Panel, under System.