According to the Gateway website, it's probably a Broadcom BCM4318E...

I thought the Broadcom wireless cards were all well-supported in 10.5.1. My Compaq laptop has a Broadcom BCM94318MPG wireless mini-pci card and it worked right of the bat with Zephy...

Here's the URL for the motherboard specs:
http://support.gateway.com/s/Mobile/Q106/Bishop/4001189R/4001189Rsp4.shtml

The onboard LAN adapter is the infamous PHY8201 ( Realtek RTL8201CL ) that may be tricky - I haven't been able to get mine to work...

The audio is a SigmaTel 9200 - I've never heard of it. You'll probably have to search InsanelyMac...

Gateway.com has all sorts of interesting information...
http://support.gateway.com/s/Mobile/2007/Apache/1014552R/1014552Rnv.shtml

im going to install 10.5.1 right now
hopefully it works just as easy

I read in another post that the PCIe Broadcom (BCM) Wi-Fi cards aren't working through any kexts (some may have gotten it, but I haven't seen how).
I have the regular BCM4318 as is listed in my system profile and it works natively... I'm typing from my Hacintosh now.