I have one simple question, Does SharePoint 2003 has Workflow? because I'm working with client who has SharePoint 2003 and I'm not sure if it has workflow or not.
Yes it does, the following link is an introduction:
EDIT: Sorry about that, 2003 does not support Workflows out of the box. There are thoug various third-party tools that let's you work with Workflows also in 2003, (2.0). Here is a blog post to get you started: http://www.c-sharpcorner.com/UploadFile/ssahmed/spsworkflow09112006025618AM/spsworkflow.aspx