Just went through the same squeaking, creaking noise coming from the front of my car. Mine was caused by the springs wearing through the insulator and slipping over the spring seat and rubbing against the side of it. Read it in Steering Boing/Creaking

I will be posting another topic in here about the 2000-2001 SSEi and the spring seats. It turns about that GM has redesigned them after 2001 and never issued a TSB or anything. DO NOT BUY THE AFTERMARKET SPRING SEATS they are the wrong type. In 2002 (from what I am told and have found out) GM redesgined the spring seats to be wider, have a different shape, and have a larger lip on them to hold the spring in place. On my car (2000 SSEi) the spring seat does not have a big enough lip on it to hold the spring in and after a while the spring wears through the rubber insulator, slips up and over the seat and rides on the side of the spring seat making the creaking/squaking noise you hear.

I just replaced my entire front sturts, bearings, seats, and mounts with the aftermarket ones. They lasted 7 days before wearing through and popping up and over the side of the spring seats. After much frustration and alot of parts stores not carrying the spring seats we decided to go back to the dealer. We ordered the parts and compared the spring seats. The new ones are built so much better. There is a substatial lip that they spring sits in and the shape is different now (the older ones being almost an oval, whereas the newer ones are almost perfectly round.) So after close to $1000 on the front end now, hopefully it will be right this time. Save yourself time and frustration if you have this problem and do not buy the aftermarket spring seats!

yes, mine was making the noise when I was going over bumps or basically anytime where the car would bounce even slightly (so just about ALL the time).