I've been logging GPS data for about a year and a half. I use an app on my Windows Mobile phone to log the GPS data, and my phone has a wifi antenna that stays in the "off" position most of the time. I met with @donpdonp the other day and he introduced me to the geomena.org project. I realized it should be possible to log access points along with my existing GPS logging. It was easy to install Airomap on my phone, so now I can log wifi points too!
This is pretty much the coolest thing in the world! I am posting from my laptop which is connected to my cell phone's wifi connection, using Sprint's EVDO connection to the internet. The software that enables me to do this is called wmwifirouter. Earlier this month they released their first final version of the software, and started charging for it. It's not outrageously priced, but you can still find the earlier free versions on the internet if you search for versions 0.90 or 0.89.