SharePoint Services 2003 does not initially come with a column for Today's Date. However, there is a workaround. Chris Johnson @ msdn wrote a great article on exactly how this works. But basically, you can trick SharePoint into using Today in a function and create whatever calculated field you need. 
I recently had to use this technique to filter a SharePoint Calendar. I wanted it to display only upcoming events and out of the box, the calendar displays everything. Here's what I found:
How to Filter a SharePoint Services 2003 Web Part Calendar to Only Show Upcoming Events
1. Create a new column with the Column Name: Today (It doesn't matter what the type is, so leave it default)
2. Next, create a column with the Column Name: Begins. In the formula section, enter: =[Start Time]. The data type should be: Date and Time. The Date and Time format should be: Date Only.
3. Create a new column with the Column Name: Date_Range. (or something). In the formula section, enter: =Today-Begins. The data type should be: Number(1, 1.0, 100). Set the Number of decimal places to: 0.
4. Here's the weird part. Go back and delete the original Today column created in Step 1. I know what you're thinking...but trust me... If you had read the article I mentioned earlier, you'd understand where this is going.
5. Now Create the Calendar Web Part by Clicking on Edit Page > Add a Web Part > Check Calendar > Click Add.
6. Create the customer view by Clicking on the Calendar Hyperlink > Settings > Create View. Under "Start From an Existing View", Click Calendar. Give the Calendar View a Name and then scroll to the bottom of the page and Select "Show items only when the following is true:" In the first Dropdown box, Select: Date_Range. In the second Dropdown box, Select "is less than". Finally, enter a zero (0) into the textbox.
That's it! When you view your page, you should now have a Calendar Web Part that displays only upcoming events. If by any chance it’s still showing all events, you may have to play with the view setting for the calendar.