In FrontPage 2003:
1. Open FrontPage 2003 to the SharePoint site you want to view the data in
2. Open the Data Source Catalog task pane
3. Near the bottom, click on the "Manage catalog..." link
4. In the resulting dialog, click on the Add button
5. Provide a Display Name and Location (the Top-Level site in a Site
Collection on the same SharePoint Web Farm)
6. All the SharePoint Lists/Libraries plus the other data sources you have
previously created there should then be available
7. Choose the List you want and drag it's Data View Web Part into a Web Zone
Admittedly, SharePoint doesn't always show its Lists and Libraries. I'm not
sure exactly why.
So, alternatively, you can use the Data Source Catalog to query the Portal's
list.asmx Web Service to return the data. Again, choose the List you want
and drag it's Data View Web Part into a Web Zone.