Updating firmware On power Mac

[navskin]

hi all i just bought a power mac off ebay for £37 and i am going to be installing Mac os x 10.2 on it. i know that i was not the best os turned out of Apple. I have been doing some reasrach on the net about installing os x and firmware updates but i am not sure about the firmware updates at all. Is it possiable for some one to explane this to me. I do come from a unix software background but not with the hardware. I can use the os fine as i have 10.5.6 on my hackingtosh now. it just this firmware thing i not sure about. the power macs soec below

Power Mac G4 450MHZ (going to be upgrading this)
DVD-Rom (keeping)
512MB(needs more of this stuff)
ATi Rage 128MB(what is this NO nvidia????)


thanks for any help you can give

graham

PS this is my frist propper mac and not a hack that why i got it and they make good itunes junk boxes. he he