We started this year's seeds indoors a couple weeks ago using old egg cartons.
Just add potting soil, seeds and water. Keep the soil most until seeds sprout.
You can transplant the sprouts to seed-starter pots. If you don't want to buy peat pots, you can make your own seed starting pots to be planted directly in the garden. Here is a video "how to" from eHow: Newspaper seed-starter pots