Just been searching google and open source sites,
i can come across open source gps algorithms that have route calculation code in there.
just incase you guys havn't looked, it may be better to start with other peoples code so you get an idea of how it's done rather than to start totally from scratch.
here is one i found.
http://www.freemap.co.il/roadmap/
hope this is helpful in some way. sorry i'm not a 'good' programmer.. just kno the basics hehe
cheers,
