Consistent compliance with Wikipedia policy is more important than your personal beliefs. Inconsistent compliance is a good sign of activist editing.
For example, if you assert something, and are presented with countering evidence from a reliable source, do you consider changing your position like a reasonable editor, or do you ignore it to argue your position?
When you join a wiki community, be a constructive editor.
Wikipedia uses the Ogg Vorbis, FLAC and WAV formats for audio, as they are not encumbered by patents (an issue that prompted the decision that MP3 files will not be hosted at Wikipedia). Software supporting Vorbis exists for many platforms...
Various online tools (such as Zamzar) are available which let you freely convert one file format into another, and can be useful when you want to upload a file to Wikipedia.