changing your computer's ip address won't help getting around an IRC ban anyway...they don't ban by machine ip they ban by isp IP...so unless you know how to spoof you aint getting back in
Not always true. There are many different kinds of bans that can be used. You can ban the hostmask, the nick itself, the ip, an isp, and even a country, and there are a few more. So yes, depending on the ban you can get back in assuming they didn't ban the isp or country (btw in order to be able to ban an isp or country an IRCop would have to have set that ban. Though those bans don't usually happen unless you are spamming the network.) Now, I can't tell you how to get passed a ban, but yes, it is possible.