help me before i pound me head on the wall!

metal contracts when cold, maybe pop the end is some icewater??

Eat more Wheaties .....

A vise can help a lot.

^ i second that

Hold the regulator in a vise, making sure the vise doesn't grip where it can damage the regulator. Use a pipe wrench to unscrew the nipple. (Try to move it in both directions, in case it is left hand threaded.)

I need to find a vise, besides drinking.....lol

If it wont come loose its probably left hand threads. Drinking and gas are a bad combo, but it helps the creative skills when aquascaping *Cheers, clink*

about 90% sure thats a normal thread on that. put a wrench or socket with a breaker bar the longer the better (do a double wrench reverse if you need the wrench longer, or slide a pipe over the wrench or ratchet but I dont reccomend doing this with a ratchet as it tends to break them), and secure the regulator with your feet while wearing sneakers (this will help absorb shock) then smack the furthest point out on the wrench or breaker bar in the direction you want it to turn with a hammer or similar hard object to crack it loose. its just seized, unfortunatly you cant torch the fittings to heat them up and loosen them. using cold would only make the metal tighter Ice wont help. your going to have to have a lot of leverage or a really good impact to loosen it.

(a vice would be the best solution...... well my vices are fun but I dont know about solutions.... )

Use a vice. Plus breaker bar if necessary.

Any chance you can find a tiny version of one of those rubber wrenches? The type used to remove/tighten automobile oil filters? And i second what Hoppy said about the possibility it's a reverse thread.

vise is almost a must imho, had the same problem when i tried to remove the adapter on my azoo reg

ok... from your picture, youve scratched the nipple all to BLEEP
theyre shouldnt have been anything on that, anyways...

get a crescent wrench, adjustable or otherwise

remove gauges
place it on the ground so that your pushing whatever you have it screwed into against the ground and your wrench should be on the nipple in the same way so that your pushing the wrench toward the ground, make sure your gonna turn this the right way when you do it... with the wrench at a slight angle off of the ground stomp it with your foot...

if that don't work, get a vice... or a strong friend