It all depends on your definition of multiple bots.
If you allready have 2 or more bots online, and you wish to link them together, then you can start a botnet. See
www.egghelp.org for this ifnromation.
If you currently have one bot on ProviderA, and wish to start another on ProviderB, then simply follow the normal install methods on ProviderB. You could then link like mentioned in the above.
If you allready have 1 bot on ProviderA, and wish to start a second on ProviderA, then you could do the following.
You allready have one bot started, you can simply create a second config file, making sure to check the nicknames, channel, user, notes and other filesnames as need be. You can simply start this bot from the same directory.
IE, using the same executable file, you can start more than one bot, in much the same way you can start the same application twice in a windows anvironment, IE MS Word (for a rather crude example).