It really depends on whether you are collecting emails or whether you are collecting emails that you are then going to use as a list of people to inform.

For collecting emails, you can setup a wufoo form in about 30 seconds and post a link to the form from your website.

If you are collecting emails that you then want to be magically setup into a list you can turn around to email out, it can be done with Mailchimp in less than 5 minutes.

If you are following this advice: (http://news.ycombinator.com/item?id=1697302) then either one will work for you very quickly.