Hi Mike
Out of curiosity, how do your lockups manifest themselves? Do you get a flashing CAPS-LOCK light, perchance?
What you are seeing is a kernel panic. If you want to debug that, Google for "magic sysrq" - it should get you on the right track. (It's a kernel configuration option that allows you to do stuff after a kernel panic.)
The lockups I get are weird. When I was dual-booting with the pre-installed Windoze (I now use VMWare - far better!) Windoze would just freeze. With a Linux kernel. it doesn't lock-up during operation (or hasn't done recently) but will lock up on reboot as the kernel is coming up. It gets to ACPI Version xxxx (or something) and stops. That's it. No flashing lights, nothing. Have to power off (remove battery), wait 10 minutes or less in a cold room, reboot.
Having control of the fan and running at level = disengaged doesn't stop this completely, especially in a higher ambient temperature (which I get here in South Australia,) but reduces the incidence. (And makes the laptop noisy and drink batteries faster ;-)
Hope this helps! Can't give much more advice on the magic sysrq as I've only had to use it once, but others on the list probably know it well.
Cheers M -- Matthew Smith Smiffytech - Technology Consulting & Web Application Development Business: http://www.smiffytech.com/ Blog/personal: http://www.smiffysplace.com/ LinkedIn: http://www.linkedin.com/in/smiffy Skype: msmiffy Twitter: @smiffytech