If you are working with a Forms page creating records in the Lead object and our Soapbox Forms for Salesforce package that helps auto-convert leads to Contacts and Accounts, you may be curious about the order of operations with respect to custom workflows. Our Soapbox Forms for Salesforce trigger fires right after the lead is inserted and before any custom workflows on the lead can fire. This means workflows cannot be used on the lead before conversion but the lead data can be manipulated post-conversion on the contact/account via workflow or custom Apex trigger.
Note that this is a little different from our Soapbox Donations and Events auto-conversion triggers, which fire after insert of the campaign member and after the Lead has been created and workflows have run. Workflows can therefore be used to on Soapbox Donation and Soapbox Registration Leads before they are converted because they will run before the lead gets converted.