How to get path?origin="osm-?"&dest="sta-?" from latitude and longitude

[Shawn]

Hello all, I have successfully setup the graphserver and everything
seems to work. Now I am looking to build a trip planner, where people
will enter their starting / ending address. How does the address or
even a lat/long get converted into a vertices?

So that i can populate the following:

/path?origin="osm-?"&dest="sta-?"

Thank you in advance,

Shawn