Sure you can! Check Create a custom list article form from Microsoft site. You will use SharePoint Designer 2007 for all the customizations. It also allows you to convert every form to HTML/XSLT and to customize it even further.

Can i customize add/edit page for list in sharepoint?
Is there a rule, or rules, for how to pronounce ough?

trough  (short o,  gh pronounced f),
thought (short o,  silent gh),
though  (long o,   silent gh),
through (oo,          silent gh),
tough   (short u,  gh pronounced f).
