The way Apple's AFP is designed, is a "single socket protocol" --- meaning that it will only ever open one outbound connection. If on another hand, you have multiple network connections coming into a Mac, then yes, likely link aggregation (port binding) would work better to balance whatever traffic.
From where you are going though, unless you have an application that is mutli threaded (opening more then one thread, which can also be run down more then one open network connection..) or unless you have a heavy incoming load of bandwidth over a single connection, you're not going to see much benefit.
i got three macpro connected through normal one gig switch for fcp edit suites. that means its on single isolated network. i tried using both the ports and aggregating them. it did not better network speed in any way as u said.
did u mean if i get some multitreaded application that will help me in any way.
or these two port are not meant for that propose. it only to balance traffic on multiple network