If I use Mt.Gox to do this, what are the specific steps I need to take?
The factors that matter for any cash-out decision are:
- Where are you located (country)?
- How much are you looking to trade?
- What type of cash are you looking to receive?
- How soon do you need access to the proceeds?
- Is privacy important?
You are specifically asking about Mt. Gox but there are numerous methods for transferring value from bitcoins to your bank. In some instances, Mt. Gox will be a good choice or the best choice, and in other instances it may not be.
In the U.S., for instance, Mt. Gox does not directly provide ACH withdrawal. ACH transfers are a method for inexpensive bank transfers. They do support withdrawing of funds to Dwolla and Dwolla can be connected (via ACH) to your bank account.
Here's the article for Mt. Gox on the Bitcoin Wiki:
And here's the article for describing most of the various cash-out / withdrawal methods: