How Do I Retreive Id Of Just Inserted Row?

I'm creating a web application that has user input on 3 seperate pages. Each page prompts the user for specific information and at the bottom of the page the user will click on the "Submit" button to post the info from the form to the database table.

Once the user has submitted the first page of information how do I retrieve the ID from the CustID column of that row so I can use the Update function to add additional info to that row when the user clicks on the submit button on page 2 & 3. I don't want to hold all the information in variables until the end in case they bail out of the form.

TIA

Steve