GPS / location tags for tasks?

My friend Jason said he would buy the nozbe iphone app and get a nice big subscription if you could integrate GPS location tagging on certain tasks and include location based reminders.

For instance, you have an @grocery store context. Your context is marked with a gps location. When you come in the vicinity of that location nozbe pushes a reminder to your phone.

Maybe it wouldn’t work exactly like that, but you get the idea