Detailed or alterate import/export

I am wondering if there is a plugin out there that allows you to specify more than just a month and year for export from a wordpress site. Like month, day, year so that posts can be synchronized easily across sites.

It also occurred to me to look for a plugin that would synchronize posts and categories between sites. Would this be possible if they are on the same host? I know cross domain scripting may present a problem but I am trying to find a simple solution to this for a client of mine.

Thanks in advance for any help.