Meg and I got a copy for her DS. You can't google map with it but there are one or two sites, (including a mobile version of google maps somewhere on google's site) that will give you a list of directions. The best you can get, image-wise, is a thumbnail so it would be very difficult to implement a mapping program via the browser.
It's slow, but that's not the browser's fault, that's just the limitations of the hardware. You'll feel like you're on dial-up again, and realize how spoiled your broadband-connected PC has made you.
You can try to use the whole Internet, but it's clunky to try to read when the page is usually much larger than the 247 pixels the width of your screen gives you. However, there are some sites out there that are optimized for the DS and other mobile device browsing. There are also a few great portals for a whole bunch of mobile-optimized sites. dssites.com is a great one of these. wampad.com I think is one too.
We should be at Jaki's party this weekend so if anyone can make it we can try to let you test-drive it, else maybe even at the meeting if the Internets are plentiful.