Biggest Tire for My Size Rims?

[radacrider]

UPDATE: I read Sheldon Browns site posted above, and what I cannot figure out is what is the inner rim measurement of my wheel? I do not want to remove the tire & tube and measure it, which I would have to to do in order to use his chart. Are there numbers which I have provided above which will tell me the width of the rim?

Thanks.

Here's a page with the specs on the Alex wheel for 700c:
http://www.kstoerz.com/freespoke/rim/119