[G4] upgrade suggestions plus

[rcbuitron at speakeasy.net]

I've noted some of the posts regarding G4s and upgrading, so I have a couple of questions as to what some of you on the list might suggest or recommend.

I have a PowerMac G4 (model 3,6 - the one with the mirror drives), 1.25 GHz, 2GB RAM (max), a PCI ACard (scsi),4 internal HDs (40, 60, 300, & 300), and the original superdrive (Pioneer 105). I have 800 firewire and USB, built-in ethernet, but do not have airport or bluetooth.

I plan to buy a MacPro in 3 months and keep the G4 as back up. I want to go wireless for Internet and network. Presently I have DSL. What do I need to upgrade on the G4 to go wireless with Apple's latest Airport Extreme 802.11n*? Will the 802.11n work with previous generations? What would be the best airport card to install in the G4 to network with the new MacPro? Is there an ecnomically lower cost solution out there, since I'm saving up for the MacPro? 

Does anyone have preference of ISP such as cable vs. phone company? I have Comcast for cable only and am considering a move to another ISP.

FYI: I do a lot of photography, graphics, and web.

Thanks for your time,
Rob