It depends on how you wire it as to how much power it will get. Is it 2 ohm stable? If it is then hook 2 wires from the positive terminal of the amp and run one to each positive of the sub. Do the same with the negative. If it isn't 2 ohm stable then you'll have to run one wire to the positive of one sub and run a wire from the negative of that sub to the positive of the other sub. Run a wire from the negative of the second sub back to the negative terminal of the amp. This will run an 8 ohm load so your power will decrease so it will more than likely be around 250 to 350 depending on the amp. If you run the subs in the 2 ohm setup and your amp isn't 2 ohm capable you will fry the amp eventually. More than likely it will be very soon as it will run much hotter than it is supposed to.
Lets say for example two Image Dynamics IDQ10's. They say to run them with 250w rms. If you have two IDQ10D2v2's they are dual 2 ohm subs. You can run those to a final 2 ohm load to the amp by wiring the dvc's in series. The type of amp you will need will be one that does 500wRMS @ 2ohm's. And is 2 ohm stable.
Dude, just make sure that the final ohmage of your speaker configuration matches the ohmage at which ur amp puts out maximum power. eg u dont want to buy a monoblock amp stable down to 2ohms and put a 4 ohm load on it. U would only be getting half the amps potential power. Just be careful u dont put a 2ohm or lower load on an amp that is only stable down to 4 0hms. (eg most 2 channel amps when bridged only r stable down to 4 ohms)