Quick Look is somewhat of a mixed "blessing" in Leopard.
Some items are simply too small or small enough to be an eye-strain - such as Word, Excel, documents, etc.
I was viewing a PDF and on a whim decided to try "Command +" and voi la, the text size increased accordingly.
"Command -" will decrease it.
Unfortunately I've not found this to work with anything else.
As well, I cannot do a Quick Look of Pages documents? Only see the Pages icon.
I'm still using Pages 1.0.2, so I cannot say if newer versions allow for Quick Look.
Anyone have the newer versions? Can you Quick Look contents?