I read around on the Internet and what I understood is that if you can attach your drive to a supporting OS first and then partition it into 2TB sizes and then convert those to MBR, your Win XP system will recognize it fine. You will just have to use a friend's computer first who has Win 7 installed. From personal experience my Seagate 3 TB external came partitioned as MBR and I had to convert it to GPT first so that I could see the remaining 1 TB of space.
Also I read at one of Tom Hardware's thread that some 3TB drives were launched that were compatible with Win XP 32 bit.
The fourth post in this thread tries to explain how they work - http://www.tomshardware.com/forum/295845-32-external-limit