So what you're saying is you have a wired connection to the net (LAN) via a wired connection to the router, a wired connection to the G5 from the router, and wireless to the iPhone and iBook(?).
Interference or bad placement of the router is the first test you want to try... the iBook has a decent antenna/reception. The iPhone is not bad.
Changing channel on the router to 1,6,11 for G/mixed mode (iBook is B only, iPhone is B/G).
- try to ping each NIC in your network... times will tell you if the problem is internal or external. ping the router, then ping something like cnn.com or something. write down the times...
- also try loading MacStumbler to see what other wireless signals are around - watch for unused channels and try using an unused one...
- Using a linksys WRT54G wireless? be daring (depending on the version of the router) and install DD-WRT or Tomato and jack up the signal strength (go from 30 milliwatts to 125 or even up to 251). I use 85 milliwatts on two routers with 7 Db linksys antennas and can send my signal over 500 feet to the shed.
- unplug your cordless phones - 2.4Mhz phones run on the same frequency
(check to see if your phones are 900mhz, 2.4, or whatever... just making suggestions to help)
I have an old SnowBall Airport that "barely" sends a signal over 15', at the time purchased it was just fine, now I use a Linksys WRT54G V2.0 with DD-WRT v24 VoIP beta 1 and two 7Db Omni antenna - there is no place within 75' my PB-G4 or HP iPaq 6325 is out of service. So think "antenna"