The N95 is a new N series phone from Nokia that will have a built in GPS. It is due to be released later this year.
Update Feb 07: Nokia have also announced the E90 and the 6110, which will be available later this year, both with in-built GPS.
There is a new version of ViewRanger that supports the built in GPS. If you already have access to an N95, E90 or 6110 and would like to try ViewRanger on it, please email me via firstname.lastname@example.org.