fusion-icon and software-update icon just copy into the apps-folder of your default iconset folder. for example: /home/you/.icons/youricontheme/22x22/apps.

pidgin trayicons are just recolored in black. copy them into:
/usr/share/pixmaps/pidgin/tray/16x16.

the exaile trayicon just copy to: /usr/share/exaile/images.

exaile trayicon and fusion-icon are made on myself with inkscape & the gimp. they are completely free, so you can use these icons in whatever way you want!
I think the pidgin icons are gpl licenced, but im not shure. the update-icon is from 2 icons of the mac4lin iconset, which i merged. i don`t know this set`s licence, i couldn`t found it on its documentation.

Any suggestions, questions or hints, are welcome.