It's tough with lights in the sky - there are so many possibilities and the descriptions are often not detailed enough to know what you're actually seeing. A few notes, though:
-Tumbling satellites can blink, which can also make them appear to zigzag.
-Tumbling/rotating satellites can become extremely bright (not as bright as the moon, but much brighter than the brightest stars or planets) for up to 30 seconds. Google: Iridium Flare. If you can pinpoint a time and location, there are applications and websites that can tell you if you saw one. A given location will see 1 or 2 iridium flares a night.
 Oops, sorry chis - shoulda read your post first!