In Sharepoint how can you copy a list item from one list to another list eg copy from \"List A\" to \"List B\" (both are at the root of the site)
I want this copying
So, the lists have the exact same or similar columns? Either way, you could create a simple workflow that runs automatically when an item is created in "List A". Since the workflow in question is relatively simple, I'd recommend using SharePoint Designer (which is free) to create it, since you can easily match up the columns from the two lists. The walk through below should be able to help you get started.
Create a Workflow - SharePoint Designer