hi u cannot do p[olicy based routing on asa even with the highest available license. cause policy based routing is not supported on pix or asa.
u can load share on 2 adsl connections with the help of 2 default routes pointing to the internet. just make sure both the internet connections are form the same asa interface.(e.g outside)
i am not sure if pix does per-packet load balancing or per destination load-balancing.
if it doe per-packet load-balancing then it will disrupt ur tcp and udp connections.
best i would suggest it use the tracking feature and get redundancy on the internet connections as compared to load-balancing.
but remember tracking feature does not work with failover.
regards
sebastan