Not sure if this is what you are looking for. Here's a post I made at other forums.
Here is one I did a long long time ago:
You can't really tell, but the maginified part is bigger than the rest. I didn't get nuts with it so it would look like the magnifying glass was closer to the background. Never-the-less, it is closer.
First I made the checkered background with the text.
Then a circular selection for where I want the magnifying glass. Save it in an Alpha channel just in case. With the selection still active, I hit ctrl + j (Paste into New Layer?). Also laid down two Guides for the center of the selection, which is easy if you have it set to Snap.
On the new layer, I hit Free Transform (ctrl + t). Holding Alt + Shift, I dragged out one of the corners ever so slightly (can drag more for a more pronounced magnification).
Loaded the circular selection that I saved and gave it a little bit of Spherize. Invert the selection (ctrl + shift + i) and add a Layer Mask.
Tada. Nice magnification. Now just a matter of making the rest of the magnifying glass.
Remember those two guides that show the center of the glass? Grabbed the Oval Marque, started at the center of the guides, held Shift + Alt, and dragged out a new circle for the metal. Made it a little bigger than the previous Alpha channel, then subtracted the Alpha channel. I was then left with the outer metal. New Layer, Fill, Preserve Transparency, and use Gradient > Mirror to colour it (white - purple - black).
Then I added other baubles. Like a soft drop shadow and the highlight in the upper-right. The highlight was just a circular selection minus another circular selection, then a touch of Spherize. I had a few other finishing touches in there, but I took them out because it was getting too muddled.
I'm not in the mood to talk about the handle.
Save PSD, crop down, and export.
magnifying a area 
[bustagut] .
Linear Mode
