Using PLINQ to speed-up calls to external services

Question

Possible Duplicate:
Parallel Linq - Use more threads than processors (for non-CPU bound tasks)

Hello. I wondering how to use PLINQ to speed-up crawling of web-pages.

I have a list of objects that is should be posted to web page. Doing it in one thread is a bit slowly.

I have tried to enroll processing loop using PLINQ's Parallel.Foreach, but it give's me only 4 concurrent tasks.

Is it possible to utilize PLINQ for such applications? Is there easy way to speed-up processing, without using Async processing model?