Mac Pro :: Moving Cursor Across Dual Displays

On my left I have a new HP 2311 23" monitor (maximum dpi 1600x900). On my right I have an old 23" Apple HD Cinema Display (max resolution 1920x1200). Both have a 16:9 aspect ratio. I just added the HP about a month ago, and this is the first I've had dual displays....so I'm still learning. I've noticed the following: If the cursor is on my Cinema Display and I move it left toward the HP, at about the top 1/4 of the screen the cursor won't cross over...it comes to the edge of the screen and stops. I have to move the cursor more toward the middle to cross over. When I move the cursor down toward the middle of the Cinema Display, it crosses over but appears a the top of the HP.

A similar thing happens moving from the HP to the Cinema Display, except at the bottom of the screen. The cursor won't cross for about the bottom 1/4 of the HP, and when I move the cursor up so it will cross, it appears at the bottom of the Cinema Display. It's almost like these screens are out of alignment....the HP sitting a few inches higher than the Cinema Display. My eyes aren't what they used to be, so the HP is set to 1344x756 and the Cinema Display is set to 1344x756 to make everything larger. However, I tried many variations of the resolution on both screens to see if that changed anything.....it didn't.

Info:
2.66 Ghz Quad-Core, Mac OS X (10.6.2), 8 GB 1066 MHz DDR3, Apple Cinema Display