My Windows XP Home computer has a mapped network drive to my MacBook
Pro running OSX.  Every time I restart my Windows computer, I am
required to login to the network drive in order to access it.  Is
there a way to automate this process so that each time Windows loads,
it logs in to the Mac?

Open your macbook in network places (like, \\macbook\)
Then mouse rightclick at needed folder "Map Network Drive" and choose
on flag "Reconnect at logon". There you can set (if needed) different
user name for connect.
Choose any drive letter where network folder will assigned and click "Finish".