Need Clarification Before Buying New PSU

Can anyone tell me if this PSU "Hiper 580W Modular PSU HPU-4B580" will work with a Gigabyte mobo "GA-8KNXP Rev 2". It says that the PSU is ATX 2.2 and I'm not sure what that is so I need clarification before I order it.

Many Thanks.

Si
8)

Windows XP Pro SP2
Pentium 4 3.0MHz 800FSB (Prescott)
Gigabyte 8KNXP (Rev 2) Motherboard
1 GB Corsair TwinX PC3200 Ram (Dual Channel)
XFX GeForce 6800 GT 256MB DDR3
40GB WD Hard Drive 7200rpm (C Drive)
120GB WD Hard Drive 7200rpm (D Drive)
120GB WD Hard Drive 7200rpm (E Drive)
120GB WD Hard Drive 7200rpm (F Drive)
LiteOn 52x24x52 CD-ReWriter
DVD-Rom
SB X-fi XtreamMusic
Zalman 400W PSU
Antec P160 Case