I thought I'd provide a bit of input into various clients for several OSes (since #free_pokemon is mainly a file-sharing channel, all the clients I list support DCC out-of-the-box (possibly excluding the last two of the advanced ones I only reference by name), so to speak)...
First, for Linux there are two well-known, well-liked GUI client. First, X-Chat.
https://www.xchat.org There's also a Windows version, but the author is probably breaking the GPL by not providing the source - don't buy it, as there are various free builds out there (I'll get to that in a second). The second Linux client is KVIrc, a KDE/QT client.
https://www.kvirc.net I haven't used it, but I know it's pretty popular.
Now, Macs... While there are some well known clients, like IRCLE, most of the well-known ones are shareware. There are, however, some less-known free clients. First, X-Chat Aqua - an OSX native version of X-Chat. The best one, IMHO (not really for a new IRC user, more for the power user).
https://xchataqua.sourceforge.net Another is Colloquy, which is not a traditional IRC client - it's probably easier to use for a new user though.
https://colloquy.info And the third free one I know of is called Conversation. I tried it out and it's pretty good, but I prefer X-Chat Aqua for it's Perl scripting.
https://homepage.mac.com/philrobin/conversation/
And now, free Windows client. Like I said, there are various free X-chat builds out there. There's a comparison of features of the main builds. Please, don't go for the pay one... Like I said, the author is possibly breaking the GPL doing that. Go for one of the free ones - X-Chat is supposed to be free. ;)
https://www.silenceisdefeat.org/~b0at/xchat/win32 Looks like the Daemon404 or SilvereX builds are the most featureful.
So... Remember, IRC is meant to be free - don't pay for a client unless you want to support the author's work (mIRC isn't the best choice to support...the author doesn't listen to requests from what I've heard - supposedly it took years of requests from paying customers to get SSL support), or have a good reason for needing a specific client. And if you're new to IRC, definitely try it out on a free client. :)
And, for those out there who really want something powerful, there are some
extremely advanced IRC clients I know of. These are
NOT for most people.
(Name gets censored - Google for a cerain 5-letter word beginning with b, and tag an x onto the end - *****x - to find it) - a well known, incredibly complex IRC client. Based on EPIC (see below). Command-line only, in most cases. Some GUIs are available, but they don't provide much functionality - it's all in the text.
EPIC - another command-line only client. Very complex, and has a very advanced scripting language. You'll probably get the most functionality by using a complex script for it - Google around or write your own.
There are some more out there, like
irssi,
ircII, etc., but I've never used or tried them, and really couldn't say much about them.
If you have any questions about IRC (I run a server - I know a fair bit about IRC in general), PM me on here, e-mail me through here, or find me on IRC (in #free_pokemon on irc.dejatoons.net under the name Chaos - I'm in there all the time, but may not be active).
Also, someone may wish to update the first post in this thread to correct the mIRC connect command given. From
/server irc.rizon.net -j #free_pokemon to
/server irc.dejatoons.net -j #free_pokemon