I got this from Dr. Oz. It's supposed to be so much healthier than regular spaghetti. I was seriously reluctant to try and waste perfectly good spaghetti with squash but it really is delicious. If you're afraid at the first, then do half and half noodles and squash. We like our noodles italian style al dente so the squash fit in well with a little crunch.
There are two ways you can cook the squash: bake in the oven or microwave. And there are a few ways you can cook it in the microwave. My husband poked holes in the skin, and popped it in the microwave for 7 minutes. I like to cut it in half and scoop out the seeds first then put it in a microwaveable dish with about 1/2 inch of water and cover with cellophane for 7 minutes. Produces about the same results. Then get a fork and scrape from long end to the other long end. It should could out stringy just like noodles. Put your sauce on top and enjoy!
By the way, it's also good as a leftover---I didn't think it would be but it's a keeper!