First of all, you can upload a picture of your suspected rooster by clicking "uploads" at the top of the page. You can select and upload the file from there, then copy and paste the link into your forum post. If you can post pictures some of the experts here can probably tell you for certain.
I'm a total newbie and have all girls (I think!) so I don't have a lot of rooster advice, but you can definitely still eat the fertilized eggs - they won't develop as long as they're kept in a cool place - and let a hen hatch some chicks for you (though if you have all leghorns they might not be willing, I think most production birds have the broodiness bred out of them).
I have heard that the lead hen will often take over the rooster role if there's not a roo around - crowing, mounting the other hens, etc. and I think they can also develop some physical characteristics like a bigger comb. Since leghorns have a big floppy comb anyway it's possible you just have a butch hen.
How old are your birds? If you have a lot of white leghorns I'm sure it's really hard to keep track of who is laying what. If your girls are already at laying age, you might try segregating the chicken in question to see if you get any eggs. That's the only way I know to tell for sure.
ETA: ok, just saw your picture. Looks like a lovely roo to me!