here is a nice very small rs232 to usb adapter can be mounted interal or external and it only cost $1.75 US.
if you are not in the US and want one let me know i can mail them overseas
http://cgi.ebay.com/PL2303-USB-RS232-TTL-Converter-Module-cable-C10-B-/270763288400?pt=LH_DefaultDomain_0&hash=item3f0abfe750
(http://i.ebayimg.com/00/$(KGrHqV,!jEE2nkD!lu!BN8Qz,(k7w~~0_12.JPG)