The LN40B530 does have a composite input, and if you have a composite only input, then you should be good to go.
The difference between the 5 and 6 Series can vary, including resolutions, panel specifications and features. Since there are several sub-categories for each (B530, B540, B550, etc), you'd have to be more specific.
You can compare models on the Samsung.com website too.
Hi, I am trying to purchase a samsung multisystem tv and don't quite understand the differences on the plug in options on the back of the tv. for example, the 40 b530 does not have an s-video plug-option in the back like most tvs. Nor does it have a composite- do I need that? Do I need that? I still don't fully understand the difference between the 5 and 6 series models. Any info will help. thanks.