Is there a maximum current rating that the Arduino can have as power? For example, can I run the arduino off a 2000mA 12v wall-wart?
Yes, the current rating on the wall wart is how much i CAN deliver max, Arduino will, only draw what it needs.
with 12v expect the regulator to get warm tho
For example, can I run the arduino off a 2000mA 12v wall-wart?
Yes you can also run it off a 4 Amp one or a 30 Amp one or even a 0.3 amp one.
Your question indicates that you have a lot to learn about the difference between voltage and current, I would do some googling around that topic before you do much else to avoid disaster.
Yeah, mike's right, I'm a noob at that kind of stuff...
And MikMo, YOU can supply current? Wow! Free energy! Or do you need to plug yourself into an electrical socket?
Yes, the current rating on the wall wart is how much i CAN deliver max, Arduino will, only draw what it needs.
;D
If you only draw a tiny current (50mA) off a 2A wall wart that is nominally 12V, you may find it is actually supplying 16V or some such because it is not regulated - they don't normally say on the label if they are regulated or not if a cheap wall wart. 16V may cook the arduino. Try measuring the output open-circuit to make sure.