wrote

I may be doing a fiar bit of driving in unfamiliar territory soon
and could do with using the iphone (4) as a satnav on occasion.
Is there a free or cheap app which is more efficient in terms of
data usage than the standard offering from Apple (Which I
presume downloads maps as you use them, if I could use an
app where preload Surrey maps and it then just had to work
out where it was and where it was going, I presume that
would use less data (i'm a long way off "All you can eat").

The free google maps for the iphone does now allow offline maps.

I don't normally bother tho, it cost so little in data that
it isnt worth farting around. I pay for the data at 5c/MB.