If you've ever looked up Persian recipes on the net I guarantee that you've seen Farzin and Roxana Mokharian's Recipes. I don't think I've ever seen an Iranian recipe site that is not a clone of this site, and there's good reason: this site has lots of small receipes based on Rosa Montazemi's cookbook (the most popular ever). Besides, I've used these myself and they work so well :-)
Recently I found Cookbookwiki, another cousin of Wikipedia, the free encyclopedia which has a whole category on Persian recipies. And just in case you don't know what a "wiki" is, it means and you can go ahead and add your own recipe or improve the existing ones.
Just to complete the post, in addition to these, many other cooking web sites such as Recipezaar have Persian recipes, but the ones I mentioned above are just way more than you'll need ;-)