I would highly recommend the GPRSbee Rev 6. It has a much easier (and more reliable!) method for waking and sleeping the GPRSbee than the Rev 4 board. Plus the Rev 6 has a u.fl antenna connector instead of the SMA that the Rev4 has, so it’s much easier to fit it inside the Mayfly enclosure. I’m deployed 6 Mayfly loggers with GPRSbee’s last week and will be putting in 3 more tomorrow. So I’ve got plenty of photos of the process and example sketches. I just need some time to publish the instructions when I’m not in the field doing installations! Hopefully I can post a couple basic sketches later this week with more detailed instructions soon after.
As for sources, we still plan to offer kits soon with the GPRSbee in them, but for now I’d suggest you order them from SODAQ or Seeedstudio.