The Old New Thing : Get Sea-Tac flight information (including gate and baggage claim) via email
by Jack Richins
"Many of them will send you email alerts when flight information changes, but the one from the Port of Seattle is the only one I know of that will also tell you when the arrival gate and baggage claim carousel number change, which is handy when you’re picking up someone at the airport. (Main entry page here.)
A useful site if you’re departing from the airport is the TSA’s Security Checkpoint Wait Times site, which gives you estimates of wait times based on data collected in the most recent few weeks."