I'm using it on Linux very successfully. There's a web front-end called postgressadmin (available from www.postgresql.org) which needs PHP3 installed which I use as well, though I'm meaning to write a Zope based admin tool.
My only problem is that I cannot get the NT version to work yet - it needs Cygwin and other stuff as well so I'm beginning to think PostgreSQL is not ideal if you need a cross-platform solution - shame.
Mmm, yes that brings me to the Interbase topic. At the moment I'm looking if I can use Interbase instead of PostGresSQL, because i'm only aware of a PostGresSQL client running on Windows, not a PostGresSQL server. Yes, I know, some people now start thinking, why do you need it on windows? Well, some customers work on Linux, so no problem, other just only want windows... and therefor I'm looking at Interbase, because it runs on both. Tom.