I just got my domain pointed here, and while it was actually quite simple, there is a catch that I didn’t see documented anywhere.
When you set up a domain via heroku and zerigo, heroku uses the zeriga api to add the domain to their own account. So if you want to then manage the dns yourself with zerigo, you cannot because that domain is already registered. Even deleting the domain from my heroku app didn’t change this.
About halfway through this (and after an email with zerigo support - which is ridiculously quick to respond) - I found out that heroku added a way for you to manage the dns for your domains. When I first started, I swear the link wasn’t there, but I went and looked again and sure enough, there was a configure link under the zerigo-dns add on where I could edit the dns for my domain. The reason I needed this was to add the gmail record to route this domains email through it.
It’s also worth noting that zerigo support said it was no problem to switch the domain from the heroku account to my own, which I may do in the future. But for now, I’m quite happy with setting and forgetting.