I was sitting in Starbucks this morning. I sent two tweets with Gravity, a twitter client supports GEO. When I browsed my tweets later, I found it showed me in two different places, with half kilometer distance.
Then I wanted to correct the problem, and found that I had not brought my laptop. Even I had, it would still be a hard chore to collect all the information from insSSIDer and submit them to Skyhook.
Got to have some more powerful software on my cellphone to do this.