to turn your laptop into an AP all you have to do is to have a wifi-card, usb-pci-pcmcia, that supports injection. Then you can use airbase-ng to simulate an AP.
Now, if a card supports master mode (depends on drivers) then you can setup an AP even with WPA encryption. The only cards that I know and supports master mode are Atheros based. You can check here:
Compatibility - madwifi-project.org - Trac
You can also download my script from 'old' forum and use it to simulate an AP. You can use it with any card that supports injection or with Atheros based cards in master mode (if supported). Check here:
How to: E-Z setup a Multi Mode WLAN based on a Fake AP - Remote Exploit Forums
I tested with BT4F and is working well at some point except some problems with the madwifi-ng drivers. Very soon I will post a BT4F full compatible version here, which will be the new home for my script.
Hope I helped.