What type of tape drive indeed. If you are using a Travan/QIC tape drive which used IDE or FDC as their interface (or externals using Parallel Port), then you will surely run into issues. Reason is that they require an additional 'shuttle port' or SCSI emulation driver, which is not available for Windows XP, and no one plans on making one either. I know Seagate makes some Travan drives with a USB interface, and those should work.
Any SCSI DAT/DLT/LTO drive should work in XP without issues.
If you are using a 3rd party SW such as Veritas Backup Exec, Computer Associates ARCServ/BrightStor, Yosemite Technologies Tapeware (to name a few), then it is recommended that you disable the Removable Storage service via Start, Run, 'services.msc' as this is used by the native Windows backup and can cause issues as two programs fight to control one device. As always, be sure to check both HW and SW manufacturers to ensure that you are using a correct configuration. model of SCSI card is often very important with tape drives as different technologies use different standards - a card that is too slow for your drive will cause backups to fail, as will a card that is too FAST for your drive (can cause shoe-shining effect, not making efficient use of HW buffers.)
If you have any specific questions, I can try to answer them to the best of my knowledge, I used to support HP drives.