I know. The first reaction is probably - Hwhy?? Well, a lot of sites seem to have been designed with Windoze!! in mind so .. a lot of them look better with the microsoft fonts … sounds logical right? cool!
I am running Ubuntu Dapper on my system here, so use the app manager that your flavour comes with 
So here is how to do this …
Just in case of a snafu, back up your /etc/fonts/ folder
Run the following command sudo apt-get install msttcorefonts.
Download the following: http://localhostr.com/files/f1f6f300383aa38e236c.tbz
Extract all the files into the “/etc/fonts” folder - don’t know how to do this? - Here you go:
sudo tar xvjpf fontconfig.tbz -C /etc/fonts/
and you are done!!
Hope this was atleast a little helpful. Let me know if there is anything else that u might want to know…