There's another thing you need to watch out for if you're using ircu.  The
default nickname length limit is 9.  With the default prefix of AIM-, you
only have 5 characters left.  This means that to send an IM to the AIM
user MattSachs you would need to send it to AIM-MattS on IRC.  You'll run
into problems if you have to AIM users where the first 5 characters of
their screenname are the same.

It might be a good idea to increase the maximum nickname limit.  This can
be done by going into include/struct.h and finding the line that says
#define NICKLEN and changing the 9 to something more sensible, like 30.  I
know people who have done this so I don't think it will be problem as long
as you change it on all servers on your network.  Then put the following
line in your imirc.conf:
        $ircservers{ircu}{nicklen} = 30;