There are 3 quick ways to copy a layer style:
Copy Layer Style
1. Click on the word Effects (A) in the layers palette and drag it to the target layer.

2. Right click on the icon marked with B and select Copy Layer Style. Right click on the target layer and select Paste Layer Style.

3. Only Photoshop CS2: Hold down the Alt key (option key on the Mac) and drag/drop the icon marked with B on the target layer.