I've just spent several hours getting my Garmin Bluecharts to work via Garmin Mobile XT, on my N95 - and YaY !!! they work!
I've now got extremely detailed marine charts from Orford Ness, to the Ille D'Ouessant with full routing, tidal heights and allsorts. I have a Garmin Etrex Legend C that I use on my boat, But the N95 screen is a bit bigger, and then there is the TV out!
Don't suppose it will cope with 30 minutes submersion at 1 metre depth of water like the Garmin - without a wet suit anyway - but its another step forwards for convergence devices!
Just have to wait for the sailing season to start now..... Good job there is that Vibe sequencer, Music Player, Camera, Video recorder, Audio book, Podcasting, etc, etc, etc......
s.