PEAR on WAMP

I've been using apache for years on linux and mysql for months in the same place. However, I'm new to php (found and ordered a great book though) and now I've installed it all on windows so I can develop stuff right in my lap instead of having to sit in range of my linux server. There's this problem of pear libraries I don't understand. Under linux, there's a whole directory tree of php source files that support pear modules. On windows, no such thing. So, I've got a sample application the looks for things like DB.php which don't exist on windows. How the heck does this work?