Yup. I've only tried this on windows 7 but the steps in XP would be similar.
Attach the drive via USB (probably using the disk drive mode in your USB connection settings) then right click the drive and choose share with --> advanced sharing. Click the advanced sharing button which probably will cause a popup asking administrator permission. Once that's done, the sharing dialogue pops up and you can check the box that says share this drive. Set permissions if necessary.
Now right click my computer, and do map network drive. Under the drive dropdown you should see your phone. In my case it defaulted to the "Z:" drive even though it's already got the "I:" drive letter. It shows up as \\MyPCName\i .
If you don't have it in the dropdown, try manually typing it in the box below using the format in the example above.