Mapping geographic data

Hello,

I've got an idea to represent geographic data with/on a svg worldmap
(http://commons.wikimedia.org/wiki/File_talk:BlankMap-World6.svg).

Furthermore the data is represented in XML with longitude/latitude
values. Now I wonder how to transform from the longitude/latitude
coordinate system into the pixel based coordinate system used by SVG.

Any suggestions?

regards,
Johannes