Does anyone know any good software to convert SD (Standard definition) video formats to HD (High definition) video formats? What are the new HD video formats?

I found out about HVD and AVCHD formats. Any conversion software? What formats are blue ray and HD-DVD using?

I found out that divx have a converter. It has an option to convert some video format to a divx HD format. Does it really work and show the video in HD?