Does a hp pavilion ze4900 have built in wireless?

Answer 1

Some do. In the specs it is listed as optional:

Optional HP ev2200 1xEV-DO Broadband Wireless Module (requires Verizon Wireless Service), optional HP hs2300 HSDPA Broadband Wireless Module (requires mobile network operator service); Intel 802.11a/b/g/draft-n, a/b/g, b/g, Broadcom 802.11a/b/g/draft-n, a/b/g, b/g, Bluetooth 2.0, HP Wireless Assistant

Answer 2

Yes it's have WLAN.