Best solution ?

[NightOwl]

I am planning (hoping to) write a database-GUI which would mostly run in
Windows but connect to a Postgressql database on a central linux-server. If
I can write the GUI so that it can also run in Linux, that would be a big
advantage. I was thinking about Python, since that runs on both platforms.
An other option is PHP (which I have used extensively in webpages but never
stand-alone).

A couple of questions remain :

1) Is Python capable of easily accessing a Postgres db? (like PHP?) (if not,
would it work with MySql) ?
2) would it be possible to design code which would (the same code) run on
Linux X-windows as on Microsoft Windows ?
3) Would these thing (if anybody knows) be possible with PHP ?
4) If 3° is yes, what would you prefer ?

Any other suggestions are welcome, as long as I am able to build a GUI for a
central database which would easily print documents too (Python has Windows
COM-support, doesn't it ?)