Use USB for internet connection, but if u dont care being charge for data, go for normal gprs,

browse the "sony ericsson" application inside phone,
find for Post tits me PosItMe.

The software can send ur location to other mobile phone using sms.
You can add some notes, let say u've been kidnapped, you can write like this, "Papa, mama! Help, i've been kidnapped by se7en, <automatic got url of map here>"

so it will be easier for the rescue team to search for u.

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I've uploaded maps for Wayfinder navigator (msia and sg), alot cheaper than before.
It only downloads data for route. Cos u already have the maps.
Even cheaper if you are always on track, cos re-routing need to download. However u can always disable re-routing.

For maps, can checkout C905 thread.
Remember, always set  assisted gps to "never" to use gps for free.