I think sl0 is SLIP (Serial Line IP), odd that that's starting, but the previous advice sould fix it.
If it doesn't there must be some init script (like diald, maybe???) at fault. Go through /etc/rc2.d (assuming runlevel 2 is your default, which it is unless you changed it). Make sure you really need all the stuff starting with an "S" This latter bit is good practice any how as things seem to breed in there :) -Jon
