Popping knees

I take my daily rides from my house. Coming out of my driveway, I immediately have to go up a pretty long hill.

Here's the problem. For about the first 5-10 minutes of my ride, especially up the first hill, my knees pop like crazy. Or, if they don't pop, they catch like they need to pop.

Once I get pretty warmed up it goes away. But that first little bit kills me. Anyone else have this problem, or a solution?

Can you do a bit of warm up stretching first? I think that would be a good idea. Also, if you have any stairs inyour house, go up and down them ten times before starting your ride.