ie http://www.oreillynet.com/cs/weblog/view/wlg/448
I've always found USB WiFi cards more convenient because you don't need any special connectors (or soldering skills!):
http://www.instructables.com/id/%22Poorman_s-WiFi%22--USB-ad...
EDIT: changed the link to "Poor's man wifi" because Google reports malware.
EDIT2: it's worth mentioning that the standing wave ratio using these home-made antennas can be higher than the ratio expected by the device manufacturer.
These returning waves can damage the power amplifier, but with most wireless cards with transmitter power output under 100 mW (IIRC more than that requires a special license in most EU) it's very unlikely (although possible) and it can only happen after continued usage.
Disclaimer: I'm not an expert, just used to play with wireless about ten years ago.