First off, are you absolutely tied to Access? Newer PDA's link very well with SQL Server, and what you are doing sounds like it would be well suited to this.

However, if you are tied to Access, the technique I mentioned requires only one button click on the PDA, which is pretty minimal. Could I get rid of the one click? Maybe, I've never given it any serious thought.

However, it requires that there be a 'receiver' program running on the desktop system. I doubt there is a way to get around this using Access, but the program can be very minimally intrusive, as it would be simply a TCPListener listening to a port when nothing is happening.

As for the mechanics, I package the data into XML and transmit over the connection. I have posted various pieces of this on this forum, if it sounds like it might suit, look around. I can post more if needed (but only for a few days, then I leave for a good month long walk).