I was just doing this for another site this week. There's a few neat services for building up a buzz before you launch.
There's a free service at launchrock.com
It gives you a nice landing page and an email signup form for people to be notified of updates. One of the neat benefits is that it is setup to encourage people to share your site with friends by incentivizing the sharing. You can setup something like if you refer 10 people to the signup form you get a 30% off coupon when we launch, or something like that. You can see it in action at mockupeverything.com
Another similar service that's paid and offers a few more features (like mailchimp integration) is KickoffLabs.com
The one I ended up going with is launcheffectapp.com which is a free wordpress integration that offers the same features as launchrock and kickofflabs (incentive sharing, tracking, mailchimp integration, links to your social media profiles, nice layout), but works with wordpress. They also have an inexpensive premium version
that is a one time fee (kickofflabs is a monthly fee)
If your site is going to be built on wordpress (which can also handle ecommerce and content management along with blogging), then launcheffect is a good choice.