async_network_io issues with BIDS
We actually ran into a similar issue at StackOverflow and Kyle blogged about it:

http://blog.serverfault.com/2011/03/16/views-of-the-same-problem-network-admin-dba-and-developer/

The problem can be a number of things:


Queries bringing back too much data (like select * from a wide table with a lot of XML or binary fields)
Client-side apps processing data row by row instead of pulling it all into memory and then doing whatever work necessary
Underpowered app server hardware (or in your case, client machines) that are paging to disk or churning on CPU.  I see this a lot on over-committed virtual machines.


To tune it, start by looking at Perfmon counters on your own machine.  My tutorial on it is at http://www.BrentOzar.com/go/perfmon, and it includes a list of counters to gather, how to analyze 'em, and how to interpret your bottleneck.