Here's my recipe for pesto. It's about as easy as it gets... (serves around 8 -- refrigerates well, so don't hesitate to make more than you need)
Wash the basil gently by dipping in a large bowl of water. Shake dry. In the food processor, process together all ingredients except the cheese and butter, until the mixture appears uniform. Add the cheese and butter and process briefly, just until they appear evenly distributed.
Serve on practically any pasta (diluted with just a drop of the pasta's cooking water), or use pesto to season salads, or spread in fancy sandwiches along with other yummies.