Take a look at this ebay auction, offering to get your xda2 working with tomtom/bluetooth for ONLY £50. :shock:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=3072445200&category=3728
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=3072445200&category=3728