Zippy,
My Thinkpad doesn't have a serial port, either. This is why I recommend:
1. A PCMCIA Serial Port card (I have one of these and it was $200 back in the day, but works 100%).
2. A Belkin USB Serial Adapter (not 100%).
3. Purple Computing (
www.pfranc.com). These guys are good

.
I recommend 1 or 3 if you're going to do diagnostic work.
Thanks,
Mitch