I've been using the IRC channel for cakephp, jquery and others for a while now without a registered password, at first I thought I would just try it out, but as these IRC channels have become more and more handy it became time for me to register properly and stop impersonating someone else :-)
I found the whole process slightly convoluted so here is the 1-10 of registering a nickname with Nickserv and joining an IRC channel using Pidgin on Ubuntu.
Pidgin was already installed on Ubuntu 8.04 for me, but if you need to install it either use the package manager:
system->admin->synaptic : search for pidgin
sudo apt-get install pidgin
Once you have that installed it should come up in the Applications->Internet menu.
Register nickname with NickServ
Settings for adding an account:
Username: !! This is where the nickname you want to register goes !!
Don't worry about the password stuff, just save the account and make sure its enabled (probably already is - the checkbox in the accounts dialog box).
There should soon be a window popping up, right about.....now. It will probably have the title: freenode-connect. There also might pop up another tab in that window with the title: NickServ.
If the NickServ tab does not appear you're in business. If it does appear, specifically with a message about the nickname being registered and about you having to provide a password or register another nick name, then the username you chose for your account is already taken on NickServ and basically you need to go through the steps of creating an account again, with a new, more obtuse nickname. If you're lucky you could get away with prefixing your nickname with an _ or swapping out letters for numbers.
Register a password with NickServ
At the stage where you have found a username/nickname which is not already taken - the freenode-connect window should be open in front of you.
/msg nickserv register YOURPASSWORD YOUREMAIL
A NickServ tab should open with instructions about completing the registration, where by you open an email NickServ sent you and copy and paste a command into the NickServ tab to verify you have access to the email account.
Thats what I did to register on NickServ! Now you can join IRC channels via Buddies->Join a Chat, then enter in the name of a channel like: #cakephp or #jquery.
Useful NickServ Commands
/msg nickserv help register
/msg nickserv IDENTIFY [nick]