ip masq with pII 266 + half life to 2 computers. (Score 1)

I'm wondering if a PII 266 will work allright to be my firewall, gateway to my cable modem for my lan of 2 computers (so i don't get charged for my 2nd ip addy, plus i'm interested in learning). We play alot of Half Life. will be able to play on the same server? and Just how hard is this to set up from a box with nothing on it..?