I have a shapefile that has geography types.
Can I convert it with a tool like shp2pgsql or is there a postgis function to do that?
You can cast the geography type to geometry by appending the ::geometry
SELECT ST_Distance('LINESTRING(-122.33 47.606, 0.0 51.5)'::geometry, 'POINT(-21.96 64.15)'::geometry); shp2pgsql has a flag to import data in a geography type column:
shp2pgsql -G .... But you can also import your data without it, by default shp2pgsql will create a geometry type.