There is 2 ways to use bitlbee. You can eather run your own instance on linux (step 0), or use a publicly available server (step 1).
Step 0. Installing your own server
In most cases bitlbee will be available in your package manager. Just install it! In distros that uses apt like debian and ubuntu the command for installing bitlbee might be:
sudo apt-get install bitlbee
In some cases the version provided in the distros default reposetorys might be old and outdated. You might consider adding the daily built packages to your package manager.
If you prefer to stay alone, you might want to change some settings (/etc/bitlbee/bitlbee.conf in debian and ubuntu) to only allow connections from localhost:
DaemonInterface = 127.0.0.1 DaemonPort = 6667
Restart bitlbee (debian/ubuntu) with
Step 1. Connecting to a bitlbee server
If you have not installed your own bitlbee server you might pick one of these or use one from your neighborhood linux geek. Servers with ssl are prefered unless you are connecting locally.
Point your irc client to the bitlbee server. In irssi the command might look like this:
Step 2. Registering with the server
First type "help" in the channel &bitlbee (the control channel) and try to get comfortable with using the help system. New users should read "help quickstart".
To manage all you chat connections you need to have a user in the bitlbee server. To register type:
When you in the future connect to the bitlbee server, you can authenticate using the nickserv authentication function of you client or just type:
Step 3. Adding IM accounts
As explained in "help quickstart2" (make sure to read the quickstart guide). To add an account to the account list you will need to use the account add command: account add <protocol> <username> <password> [<server>]. For instance, suppose you have a Jabber account at jabber.org with handle firstname.lastname@example.org with password QuickStart, you would:
account add jabber email@example.com QuickStart
For more information about the account add command, see help account add. When you are finished adding your account(s) use the account on command to enable all your accounts.