I've dabbled with arch for a couple years and like it a lot. Arch has really good support on their website. To get you started here is the wiki page for installation, with links to about anything you'd need for installing Arch on a new box:
http://wiki.archlinux.org/index.php/...y:Installation
And here is the Official Arch Linux Installation Guide:
http://www.archlinux.org/docs/en/gui...all-guide.html
The basic plan is to download and burn an install CD. I used just the base install, then got everything else from their FTP site. With pacman that is extremely easy since you can just do pacman -S to install a new package with all dependencies taken care of. As long as you have a fast internet connection I'd recommend going that way. If not, you may want the full install CD instead of the base.
As far as what to write down, make sure you have all your networking info and hardware info. The installer will ask you lots of questions to help set up that stuff and get you to the ftp repository. Once you are that far you should be good to go.
Also get a ID on their forums if you haven't yet. I usually get good answers to my questions within a few hours at most.
I've not tried using it on a laptop, but that config you have is plenty good enough. My first Arch box was a 1998 vintage Pentium II 350Mhz with only 256 meg of ram in it, and Arch was screaming fast on that. The only worry I'd have is if the built in modem is one of those Winmodems that runs only with Windows. If you have that it might be a problem, otherwise you should be fine.
Good luck,
Ralph
