Im using mandrake 10.1 community edition and i want to change my computers name. I'm refering to the name as seen on the internet e.g pinging [computername] instead of an ip. I know its in one of these menu's but i've looked through and cant find it.

open up a terminal (ie konsole)
su
hostname <name>
that does it.
Note that you cannot simply ping <name> and expect a reply unless your IP is registered with a DNS. If you are on a LAN and only pinging locally, this is different. (You have to buy the name). If you run under a cable company they will sometimes have a name set up for you, but it usually includes your ip and ur isp ... so whats the point
Alternatively, if you want to have an easy name to remember for accessing your computer over the internet check out www.dyndns.org which will help you register your ip to a dynamic dns account (for free!) theres many others out there as well. This will give you a hostname like mycomputer.ath.cx or something similar (they have several domain names).