I believe Matt has recommended 1 off ebay to a few people. Cant remember what one it is thou except i think it was orange? Have a search thru the posts on here.
I use an OP-COM connected to my laptop which i find very useful, but i note from your original post you dont have a laptop. Might be worth getting a cheap lappy from somewhere like cash converters or off a friend etc. OP-COM works with windows XP.