At this point you should have an idea of what yoga is, what the styles are, and what you need to get started.  All that's left is to do it.  Are you ready to find a studio but have forgotten which style you wanted to try?  With names like Iyengar and ashtanga, it's no surprise.  To refresh your memory, a short description of each type of yoga is provided below.

Iyengar: Focus on alignment.  Uses props.
Ashtanga: Aerobic, flowing style.
Viniyoga: Focus on breath for deeper stretches.
Kripalu: Gentle, slow-paced style. Meditation in motion.
Bikram: "Hot yoga" for flexibility and detoxification.
Prenatal: Uses traditional postures appropriate for pregnancy.
Other/hybrid: Types that are combined by instructors seeking new styles.

Iyengar

The Yoga Barn
660 NW Gilman Blvd
Issaquah, WA
(425) 427-0038

Yoga Centers
2255 140th Ave
Bellevue, WA
(425) 746-7476

The Center for Yoga of Seattle
2261 NE 65th St
Seattle, WA
(206) 526-9642

The Yoga Tree
3601 Fremont Ave N.
Seattle, WA
(206)545-0316

Ashtanga

The Ashtanga Yoga School
1412 12th Ave
Seattle, WA
(206)923-1050

Viniyoga

The Yoga Barn
660 NW Gilman Blvd
Issaquah, WA
(425) 427-0038

Kaya Yoga
5004 S. Genesee St
Seattle, WA
(206) 760-1917

The Yoga Tree
3601 Fremont Ave N.
Seattle, WA
(206)545-0316

Kripalu

Christy Fisher Kripalu Yoga
4519 1/2 University Way NE
also: 12577 Densmore Ave N
Seattle, WA
(206) 568-5128

Bikram-method

Rain City Yoga
5014 Roosevelt Way NE
Seattle, WA
(206) 729-9642

Bikram's Yoga College of India
1054 N 34th St
Seattle, WA
(206) 547-0188

Prenatal

8 Limbs Yoga Center
500 E Pike St
Seattle
(206) 325-1511

Seattle Holistic Center
4649 Sunnyside Avenue N
Seattle, WA
(206) 525 9035

Other/Hybrid

Samadhi Yoga
1205 E Pike St
Seattle, WA
(206) 329-4070

Seattle Yoga Arts
109 15th Avenue E
Seattle
(206) 784-6316

8 Limbs Yoga Center - Wedgewood
7345 35th Ave NE
Seattle, WA
(206) 523-9722