I am currently withing with the beta version of php 5.3 and i get a bunch of error when i do stuff like namespace codereck; use codereck;, and the new syntax. is there a way to add this to the editor but still allow for the regular error checking to still work?

I think phped will support php 5.3 specific stuff the moment it comes with php 5.3 in the box. It is not possible to expand the "vocabulary" of the editor I'm afraid.

Well is there a way to turn off error checking?

As of March 22, there was no final decision on what syntax to use for namespaces in php. Try to google for Marcus Boerger post named "[RFC] Namespace syntax decision" and you'll see that.

Regarding syntax checking, you can turn it off. See tools->settings->Code Insight, settings, Instant Error Analysis, enabled.