[pgrouting-users] distance using lat/lon

[bino oetomo]

Dear All ..
I just install PGROUTING and load it with indonesia OSM data from 
cloudmade per http://www.pgrouting.org/docs/howto/osmdata.html

I try to understand how to use it , also I try to understand url posted 
at 
http://lists.osgeo.org/pipermail/pgrouting-users/2011-November/000868.html
but my lame brain can't handle it.

So, if I have i.e :
Source : -7.779869491959156,110.37660468220906
Target : -7.7779241824267284,110.36789018511968

How to count the routing distance/cost by : shortest_path_astar , as 
stated at http://www.pgrouting.org/docs/1.x/astar.html

Sincerely
-bino-