Creating a Geospatial database on Amazon RDS

Have you tried http://postgresapp.com/ ? Doesn't get much easier than that.

Btw., depending on your geo needs it might sometimes be simpler to use earthdistance instead of PostGIS:

https://gist.github.com/norman/1535879

http://www.postgresql.org/docs/9.1/static/earthdistance.html