XCN is an XChat script (written in Perl, of course) that queries DCC bots for their lists of served files and searches these lists based on user input. Effectively, making use of DCC bots rather Napsterlike.
Randfunc is an IRC bot, written in Perl, featuring things such as database interaction (for channels, chanusers, admins, suspends, etc.), an XML configuration file... and, of course, a few commands.