Most motherboards do not have built in WiFi yet, and this one is no exception. Grab either a PCI or PCI-E x1 WiFi card if you absolutely need to have wireless connectivity for this machine.
There are also USB sticks that can provide WiFi connectivity if you don't want to get a card. However, they tend to be flakier than the WiFi cards, so you are probably better off with the internal solution rather than external.
one more question, should i get one with an antenna or without?