InfoPath forms are a great way to capture information from
a user. They can be presented to the user as a web form right
within a SharePoint site. User can fill out the form and it gets
submitted to the form library in your site. The form library then
has the capability to route that form for approval using a
workflow. SharePoint Designer can be used to create that workflow.
Workflows can also be modeled in Visio and then transferred to
SharePoint Designer. All of this and more is demonstrated in this
video.