If native drivers doesn't work out for you, you'll probably want to uninstall the version of ndiswrapper that you have and replace it with the latest version. Check the ndiswrapper thread in tips and tricks to see if that helps.
Have you tried grabbing the latest version of ndiswrapper from their website and giving that a go?
Also, check their wiki to see if anyone has had the same problem.
Type dmesg at a command prompt and look for relevant lines (there will be lots of stuff returned by dmesg - you could try "dmesg | grep -i ndiswrapper" (without the quotes) but it may lose some important info).
Does all other web access work, have you checked which ports msn uses, and if they are open in your firewall?
How doesn't it work? Fail at signin? What version of GAIM are you using?
ndiswrapper section in tips and tricks - may be a little out of date.
To get ndiswrapper fully wokring you may have to get the latest version as source code from their website and compile it.
Check out the pinned link on internet connection sharing at the top of this networking forum. You'll probably also be interested in reading the howto on samba that can be found here.
Please post back if there's any problems.
Where did you try to untar it to? You should aim for somewhere in your home directory although you will probably need to be root to install the firmware anyway.
kppp is probably the way to go then. I'd check your security level, firewall (probably causing the problem as it is probably configured for ethernet) and that you have the correct dns servers in /etc/resolv.conf
You'll probably want to add that to /etc/bashrc (or your distros equivalent) - if you run it as a user you'll only see processes due to that user, run it as root to see everything thats going on.
There's some interesting stuff on that link - but aliasing something to ld is just plain stupid!!
Running it now but can't really tell any difference - except that it breaks the ish theme slightly (probably specific to running the i686 verson on x86_64)!
It sounds like the card is configured OK, so I'd double check that the AP are ready to give you an IP address (have dhcp enabled, aren't filtering by MAC address).
If they have them, it could be worth checking the AP's logs.