As usual, a good article from U2U on “Showing list items from another site“. This is very useful with the DataView web part, though as noted at the bottom there are some limitations – particularly the lack of views, and editing. It’s worth reading the article, but in short (for my own memory), in SharePoint Designer:

1. Manage data sources
2. Connect to another Library (by which they really mean ‘Site’ – use the site url, not the library url)
3. Drag data in as DataView web part
4. Use smart tags to set up columns, filters, grouping, pagination, etc..