I'm using Beatbox to access Salesforce's SOAP API. I can query for a series of Leads—
SELECT Id FROM Lead
Does anyone know how I can create a URL to view each Lead on the website?
You need to find out the URL of your instance (naX.salesforce.com) and generate a link pointing to:
http://naX.salesforce.com/<leadId>
If the user is not logged in it will ask for credentials and redirect him after the login is completed.