Is it possible to list all the content that was added to a site in a date range? E.g. show me all content added yesterday.
This is for MOSS 2007.
You can use Content Query Web Part to display eg. all documents in entire site collection based on custom filter/query.
To use time span as filter take a look at this links (both links for 2010 but it's same as in 2007):
You will encounter some issues if your goal is to combine different content types (eg. mix list items with documents). Also customization is sometimes tricky but there are tons of examples out there eg. Customizing the Content Query Web Part and Custom Item Styles
Addition
Some extra links regarding Today issue in 2007:
I create web part page, and make a dashboard out of it. I set each list to display with anything that's been modified in the last 7 days.