How does one change his domain name without losing hits?

Yeah, seriously. Did you expect you'd just drop the old domain and you'd still get the same visitors?

I changed my blog's address from poromenos.org to korokithakis.net and 301d everything, I saw zero reduction in visitors. If you tell Google you're redirecting (from inside Google Webmaster Tools), they'll even oblige and rewrite their own URLs to the new ones, preserving PR.

Redirects are also the better way of having content at yoursite.com and www.yoursite.com, etc.

Redirect and avoid content duplication.

Yes, and make sure to notify Google of the 301 from inside their Webmaster Tools site, as well. Also, run a Yahoo Site Explorer search to see who is linking to you, and email all those folks to have them change the links to your new domain.

A caveat: You may lose search engine rankings for a few weeks. My site was ranking #4 for a specific keyword and I changed the domain. Did everything right--301 redirect; notified Google. I have a service that checks my rankings every day. I noticed the site dropped from the rankings ENTIRELY for 3 weeks!

But then it came back with the new domain...and at #1 for that search term. :)

Just know that even doing everything right means you may still have a waiting period.

By the way, I'm shocked this guy just let his old domain name waste away. Fortunately, it appears he still has the name. If the OP is reading this, for Pete's sake, do a 301 before you lose all your Google juice!