I live in Washington state and work in Oregon.  Washington has no
state income tax, and Oregon does.  I thought that I had to pay Oregon
income tax, but recently learned that others at my job who also live
in washington don't.
Do I have to pay Oregon taxes even though I live in Washington?

Hi mspetrie,

Yes, you (and your coworkers) do need to pay Oregon Personal Income
Tax even if you live in Washington. They even have a special form for
it called, --not surprisingly:

OREGON Individual Income Tax Return FOR NONRESIDENTS (FORM 40N)

Reference:

PART YEAR AND NON-RESIDENT PERSONAL INCOME TAX INSTRUCTIONS
http://egov.oregon.gov/DOR/PERTAX/docs/2004Forms/101-045-04PY.pdf

This can be confirmed here:
Toll-free within Oregon:  1-800-356-4222

OREGON 2005 Instructions for Estimated Income Tax and Form 40-V Payment Voucher
http://egov.oregon.gov/DOR/PERTAX/docs/2005Forms/101-026-Inst04.pdf

So sorry... but then, you have been paying all along...  You may want
to show this to your coworkers.

~~Cynthia

Search terms used at Google:
Oregon "personal income tax" "non resident"