In order to log on to BotNet, you need a Bot ID and hub password (chosen by you). Only BotNet administrators (Skywing) can create unique BotNet bot accounts. You can contact BotNet administrators in the Battle.net Op [vL] channel at USEast, or send them a private message on the forum. Open requests for BotNet accounts will be deleted.
By "account," I mean the Bot ID and hub password you send in 0x01: log on to botnet.
Unique user accounts (which other users on BotNet see you as if you're logged on) can be created yourself using 0x0d: account management. It is not necessary that you log on to a BotNet user account, it simply makes it easier for other users to identify you.
In order to send messages on BotNet, you must be on a database. There are some databases that are publically available just for chatting, such as the MiniCouncil database. Ask around for the password, because I don't know it!
BotNet protocol specification
Server_Version_Enhanced:
http://www.valhallalegends.com/files/BotNetProtocol.txt
Kp_Version_1:
http://www.valhallalegends.com/kp/bnsp-latest.txt