plugin interface / list

[webograph]

hi,
i'm about to write a script to play various audio files. what i want to write 
is a directory (module) containing wrappers around various players that supply 
a player object (inheriting from a general player object defined earlier) and 
an entry in a list of mime types (which player is for which type).
i've tried various forms of import and __init__.py configurations, but i 
repeatedly have problems with the following steps:
- create an object inheriting from the main script
- fill the dictionary declared there
(i guess the problem is actually the same)

is there a standard way of doing such things?

thanks in advance
webograph