Airport transportation

Sea-Tac Airport is south of downtown Seattle and the wedding events. 
Map of Airport 

Taxis:
Taxis can be taken from Sea-Tac airport to the three wedding hotels for approximately $40.00.  The Taxi stand is located in the main parking lot off of the terminal.

Light Rail:
The Link light rail recently opened and can be taken from Sea-Tac airport to downtown Seattle. It takes approximately 40 minutes to get downtown and costs $2.50. The Link light rail service runs from 5am to 1am on Monday through Saturday and 6am to midnight on Sundays. Trains arrive and depart every 7 1/2 to 15 minutes, depending on the time of day. Once you arrive downtown, get off at one of the last tunnel stops and you can either take a taxi the rest of the way to the hotels, or take a bus.
Light Rail Website

Bus (if you have taken the Light Rail to downtown - get off on University or Westlake stops):
Bus fare is between $1.50-$2.00 depending on time/route. For those staying at the Residence Inn, from downtown you can take the #70 bus & get off on the Fairview Ave N & Valley St stop - the hotel is right there (bus should take about 15 minutes). For those staying at the Watertown Hotel or University Inn, take the #71, #72, or #73 bus routes and get off on the NE 42nd St & 8th Ave NE stop & walk 0.1 of a mile East to Roosevelt (bus should take about 20 minutes).
Bus Website 

Rental Cars:
Rental cars are available both at the airport and off-site with pick-up/drop-off services:
Car Rental Website

For those of you planning on hanging in the Seattle area for a few extra days (and traveling by bus, ferry, etc), you may want to look into obtaining an Orca card. Until Feb 1, 2010, these can be purchased for free:
Orca Card Website