PLEASE HELP AIRPORT ON THE EMAC

Brand new emac came in yesterday pluged it in everything seemed to be working fine. Love how it looks even if it is big . Then I tried to wirelessly hook it up to our wireless rounter... NO GO the emac doesnt seem to be picking up our wireless or any of the other wireless rounters around our house. I am running an 80211b rounter and I know this will work on macs because my friends ibook hooks into it easily. PLEASE HELP IF I HAVE TO SEND THIS BACK AND WAIT FOR IT ALL..... OVER...... AGAIN.... grrrrrr