1. Go to mIRC Options (Alt + O) -> Connect -> Options -> Perform add your network.
2. In the edit area type a list of commands you'd like to perform upon connecting. I think you're going to have to press ok and then re-open the perform dialog, for me it doesnt seem to save more than one network at a time. Maybe it's my mIRC though.
One for FreeNode and one for DALnet. Make sure perform is enabled.
Alternatively, when mIRC starts up:
On *:Start: {
server freenode-server -j #some,#Channels,#Here
server -m irc.dal.net -j #DALnet-Channel
}
-Andy