I got a Gateway MT6458 laptop computer back in October of 2007. One of the first things I did was to resize the Vista partition, giving me about half the disk to install Linux on for a dual-boot system. I used the Xubuntu version of the Ubuntu Linux distribution.
A fly in the ointment was that Xubuntu did not recognize the built-in PCI-E wireless card, a Marvell Topdog card. My solution to this point was simply to carry an Atheros-based PCMCIA wireless card and plug it in if I was using Linux.
Unfortunately, I seem to have misplaced the PCMCIA card.
So I looked for people who had managed to get the Topdog card working. The main problem I had, it turned out, was trying to be too specific in my search string. Trying to locate “xubuntu gateway mt6458 wireless” didn’t work, but when I tried just “ubuntu marvell topdog” I hit paydirt. That thread has step-by-step instructions (not all in one comment, though) and a link to a working driver archive (on page 2).
To summarize, once you’ve unpacked the driver archive:
sudo ndiswrapper -i NetMW14x.inf
sudo ndiswrapper -a 11ab:2a08 netmw14x
sudo ndiswrapper -m
sudo depmod -a
sudo modprobe ndiswrapper
As another commenter noted, I had to repeat the last two commands, but my Xubuntu now can do wireless via the built-in card.