PF load balancing

Hallo, I have two internet connections and I want to use both with a
round-robin load balancing, only for outgoing connections. I found
on the web various solutions, but I did not manage to modify them
for my scenario. One internet
connections is a normal adsl, there is a modem that I connect to the
OpenBSD router, the interface receives the dynamic IP using dhcp. The
other connection has a static IP address and gateway. Now I'm reading
the PF documentation, but while I study I need a "fast and dirty"
solution that "just works". Can someone help me?

Thanks, Elerdin.