For you MOSS 2007 WCM / Publishing site developers out there, check out the two articles just for us recently posted on MSDN. These were written by a MCS consultant who worked on the Hawaiian Airlines WCM site.
To the latter article, there's one part where it shows how to create a content type using a Feature. One thing to note is that the code sample (section 9a) does not show a content type that inherits from the Page content type which all content types that are used in conjunction with page layouts in Publishing sites. Instead, I'd recommend you make sure you inherit from the Page content type which has an ID of 0x010100C568DB52D9D0A14D9B2FDCC96666E9F2007948130EC3DB064584E219954237AF39.