Am about to head overseas armed with a Canon DSLR and an iPhone 3GS.

Wondering whether anyone uses their iPhone 3GS to log GPS data for use with their photos taken on a real camera?

If so, I'd be interested in hearing what App you use and what software to merge the GPS data with the photo details.  Haven't done this before!

I realise the iPhone GPS accuracy won't meet that of a stand-alone GPS logger, but to be honest, a rough location is going to suit me fine and beats carrying and charging another device!

Any advice welcomed!

Cheers