Second Cooking Light. Their recipes are also available online at www.myrecipes.com (along with a bunch of other magazine recipes). I also like www.budgetbytes.com/
It's not specifically healthy cooking, but everything I've made has fit right into my plan. The worst thing, health wise, was probably the jalapeno mac n cheese and even then it was only about 600 calories per serving. Oh yeah, skinnytaste.com too.
For cookbooks, the ones by Ellie Krieger are good. She has a few of them and they're available used on Amazon for very cheap.