Slash Commands
The slash command is "/equus" or "/ei" for short. You can use these in the following context:
"/ei" or "/ei all" - Summons the fastest available random mount, based on your location and skill.
"/ei " - Summons a mount from the given filter, e.g. "/ei blue", "/ei raptor" or "/ei fastground".
v1.5 onwards: "/ei " etc. - Summons a mount which is in all of the given filters, e.g. "/ei blue raptor fastground".
Please note, all filters should be spelt exactly as shown in the Equus interface. Mis-spelt filters will be ignored by the addon.

Useful Macro
Here's a useful macro that, when clicked, will either cancel your current mount if you're mounted, or summon a random mount if you're not (similar to clicking a mount on your action bar) (Note: This will not dismount you if you're flying, to save some painful landings).
/script if IsMounted() and not IsFlying() then Dismount() else Equus_Mount("All") end