You can check with the OSU extension or local nurseries. I know Portland nursery has a schedule.

OSU publications are accessible from this page.
http://extension.oregonstate.edu/gardening/

Click the large graphic at the left (Growing Your own Food), then check the planting chart on page 7.
The direct link is http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/21092/e-em9027plantingdates.pdf?sequence=6

Portland is in Region 2

Here is a link that might be useful: OSU publications catalog

Thanks very much for the help.

Paul

Also check out Sunset's "Western Garden Book". It has an awesome chart of when to plant what vegetables. What's great is that it was specially written for gardens in Oregon and the western US.

oregon tilth also has a great section on growing charts.