How to find complimentary mosfets???

Hi.
I am building a multiplexed high power LED display, and I would like to use mosfets to control it. I would like to make a 4 x 6 display, using 6 N channel mosfets, and 4 P channel mosfets.
I once found a way of, from one mosfet (say IRFZ34N --- N channel), find the complimentary (p channel) mosfet.
Do you know a way of finding them???
Thanks in advance, and sorry for my english.
Manuel

Go to IRF.COM get the IRFZ34N data (55V 29A).
Use the FET selector guide
PRODUCT LINE
HEXFET Power MOSFETs
P-Channel
VBRDSS (V) =55 volts
ID=28 amps
There are 3 choices.
You could use lower voltage.