New to the scene:As of 2011 era, try ST-Links pgMapSpatialKit. The software is freeware, and works with ArcGIS 9.3 and up/ 10.0 / 10.1 / 10.2.
The download has a nice PDF to document the capabilities, which include viewing, editing, etc.
As I know, many people have been using this small useful tools since last year. The tool work with PostgreSQL 8.3/8.4. Not work for PostgreSQL 9.0 yet. A new release for working with PostgreSQL 9.0 should come out very soon.