Here is a collection of very useful brass resources at Selmer's website.

http://education.conn-selmer.com/content/brass_resources.php

Here are some direct links to a few things:
Cornet, Trumpet, Mellophone Fingering Chart
Cornet Warmups
Euphonium Fingering Chart
French Horn (single) Fingering Chart
French Horn (double) Fingering Chart
Trombone Slide Chart
Trombone Slide Chart (F Attachment)
Tuba Fingering Chart

There are some other useful resources there, so check it out!