tom tom sat nav with an iPAQ pocket PC

Hello, another technology question to keep you on your toes :):):)
I have a Compaq iPAQ pocket PC with bluetooth.
I also have a Nokia 7610 phone.
What can I do to get sat nav on either/both of these items as cheaply as possible?
Tom tom?
Sorry to sound like a pillock but I don't know much about this stuff, someone just said I could save some money by using my PDA,
Many thanks,
George :)