For a more versatile alias you can do something like this:
alias c { return $+($chr(3),$1,$2,$chr(15)) }
Usage: $c(<ColorNum>,<Text>)
Where: ColorNum is a mIRC color value from 0-15(Press CTRL+K in mIRC for more info). Using Double Digits Is Recommended(00,01,02,etc).
Example: //echo -a $c(12,Hello) $c(04,There) $c(07,How Are You) $+ $c(03,?)
Outputs: Hello There How Are You?