Hi I'm building a new PC and I'm almost done. All that's left is the power supply, but I don't know how much wattage or what this Ampage is. If you could help me out lemme know what you think I'd truly appreciate it. Here are my specs:

Case: A380 color (has 3 fans included)
CPU: Intel i7 860 2.80 GHz
Motherboard: Biostar Tpower i55 lga 1566 intel p55 atx intel motherboard
Memory: 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1066
Video Card: NVIDIA GeForce 9800 GTX+ 512 MB DDR3 (might later add 1 and use sli)
Hard Drive: Hitachi 1 TB

If I'm missing anything please let me know. Thanks for all your help.

Just looking over your specs quickly I think you should be able to get by with a PSU in the 500-600W range. This may be a little overkill but it allows you a upgrade path in the future. The thing you will want to remember is to buy a quality PSU. They may be a little more expensive in the beginning but will pay for themselves in terms of reliability and power in the long run. Many cheaper brands tout high wattages but their claims are unrealistic based on their hardware. Look for names like Antec, Enermax, Corsair, even PC Power & Cooling (agruably the best)

Hope this helps