Well there is also that chat button on the srp menu that goes to the freenode's webchat - you still have to pick a screen name that's not used on freenode though.
The problem is that there isn't anything else that is better. there were two other chats that were running on our server before we switched (one java and one php) and they were much much worse than IRC. Slower, crashing all the time, using huge amounts of memory on people's computers, allowing very limited number of people to be in chat at the same time...
And you couldn't use them with anything mobile either.
It seems to me that IRC offers way too many options to use it and that makes it difficult for people to pick one and use it.
I think the instructions how to set it up and use it through a number of different ways are pretty good and easy to follow, and to improve them there is a need for specific feedback:
Using the SRP Chat - Straight Razor Place Wiki
I don't see what can be more easy than 'click on the ichat link on the menu and enter a screenname'.