[mechgrad]

Plenty of schools will you just usually will have to take some undergrad courses like jlund said to make sure you have the knowledge.

Source: doing this from a mechanical engineering degree this year.

What I did, went and talked to my local university's CS advisor to see how I could pursue a degree in CS and they suggested that instead of a second bachelors I go for a MS.

So if you have a local college you would like to go to or if your alma mater has a degree program that interests you I suggest making an appointment with an advisor to talk about options. Many times you can start off non-degree and switch to degree seeking grad after a set amount of hours.