Regarding the new on-entry visa exemption regulations, here's an update
from people who have crossed the Cambodian border since 1 October :
please be advised that visa-runs are operating 'business as usual'
but - immigration officers have begun marking passports,
that is, they have begun the process of counting the
number of on-entry stamps in your passport.
That doesn't necessarily mean they will enforce
the '2 runs you're out rule' but it appears
that they are moving in that direction.
There's no reason for people to panic.
If you are planning to come to Thailand,
be sure to apply for a 60 day Tourist Visa
at your nearest Thai consulate or embassy
before you hop on a plane bound for Bangkok.
If you've already lined up a job, ask the manager, DOS or director
to send you a signed letter of employment on school letterhead
so can apply for a Non-Immigrant B Visa
before you depart.
If you're already
in Thailand - and doing 30 day border runs,
ask your employer about sponsoring a Non-B and/or work permit.
That's the best advice I can offer at the moment.

With regard to visa-runs, I've updated
The Master Index Thailand FAQ.
If anyone has something to add to what I've written below, I'm all ears:
Q2.2:
I'm already in Thailand and my visa is about to expire.
A2.2: Don't panic! Many expats are in the same boat; most of them just do a border run. That means simply crossing one of Thailand's borders into a neighboring country and coming back with a new visa. For those who prefer a little company and a helping hand with the paperwork, there are several visa-run bus services available to guide you over the border and through the so-called U-turn. The Bangkok to Cambodia run takes roughly 4 hours each way (depending on traffic) plus 30 minutes to several hours at the border itself while you stand in line for your stamps.
note 1: Don't forget to bring along one passport photo, which will be stapled to your Cambodia visa app!
note 2: More and more visa-run services are crossing the border at Ban Laem Village in Chantaburi, a recently opened border south of Poipet which is less crowded and a lot faster than Poipet.
About Poipet: If you do cross the border at Poipet, please be aware that there are gangs of highly skilled child pickpockets waiting on the Cambodian side of the border. Just be smart: leave your jewelry & digital camera on the bus or at home, and put your cash in a safe location, preferably
not in a backpack or wallet. These kids are clever; they know where to look and how to distract you for the brief moment it takes to relieve you of your cash.
update effective 1 October 2006: people who enter Thailand on a 30 day on-entry visa will be allowed to extend that visa twice, allowing a total stay of 90 days. Details of the new rules can be found
here. If you are planning to arrive in Thailand without a firm job offer, [i.e. without a Non-Immigrant B Visa] it would be a good idea to visit your nearest Thai consulate or embassy and apply for a 60 Day Tourist Visa
before departing for Thailand. Depending on where you apply, you might get a multi-entry tourist visa, which would be ideal. In plain English, any visa is better than the 30 day visa exemption.
Keep your eye on the
Thai Visa.com Forum for the latest news and updates!
http://www.alexvisarun.com/ (Alex Visa Run / Bangkok to Cambodia
-> 1,900 Baht)
http://www.smsilom.com/ (SM Travel Visa Run / Bangkok to Cambodia
-> 2,000 Baht)
http://www.thaivisaservice.com/ (Sawasdee Transport / Bangkok to Cambodia
-> 1,800 Baht)
http://www.thaivisarun.com/ (Quick Thai Visa Run [
the one I use] Bangkok to Cambodia
-> 2,000 Baht)
tour@finedaytour.com (Fine Day Tours / Bangkok to Cambodia / E-mail or call
02 682 8939 ~ 41 -> 2,000 Baht)
http://www.eastmeetswesttravel.com/cmb/viewvisa.phtml (East Meets West / BKK to Cambodia
-> 2,000 Baht)
SugarFreedom@Hotmail.com (Freedom Tours / BKK to Cambodia / E-mail or call
01 347 4275 -> 1,900 Baht)
http://www.jackgolf.com/eng/visaService/visaService.asp (Jack's Golf / BKK to Cambodia
-> 2,000 Baht)
http://www.freewebs.com/visarun-chiangmai-maesai/ (M&J Chiang Mai to Mae Sai
-> 760 Baht + visa)
http://www.jrtravelthai.zoomshare.com/ (J.R. Travel / Pattaya to Cambodia visa-run
-> 2,000 Baht)
http://www.thaivisa.com/forum/ (Thai Visa Forum
-> Thailand's trusted online visa resource
!)
http://www.asiatradingonline.com/visas.htm (Asia Trading Post
-> border updates)