When you say last summer, do you mean this very one that just past, or the previous one (2009)?
Anyway, my gf's '01 PT Cruiser has been making an unpleasant groaning noise the past couple of winters in the morning, when cold out, for the first several turns she makes.
After getting nagged to death a couple weeks back about not caring about her PT Cruiser as much as I should, I picked up a bottle of power steering fluid, and started doing some research.
We found out that there's a sort of filter screen in the bottom of the power steering reservoir on her car, and that over time, carbon gunk builds up on it. When the car is cold, this restricts the fluid from flowing freely through it, which then causes the power steering pump to groan, since it isn't getting enough fluid.
What we had to do was suck out as much fluid as we could reach, scrub the screen with a modified tooth brush, and then top back off with fresh fluid.
The result was a nice quiet power steering system in cold mornings, and a happy gf once again, who no longer believes that I'm neglecting her car's feelings. Happy gf's are always better than unhappy ones.
So, that's something you might want to talk to your mechanic about.
Ask him if there's a filter in the power steering reservoir, and if he would be willing to see if its dirty. He might want to just replace the entire reservoir instead of taking the time to scrub it clean, however.