We have automotive classifieds site which has listing of used cars. We would like to use microdata format. What would be approparite microdata structure/schema for classified site ?
Would http://schema.org/ItemList be suitable ?
I did a quick look. ItemList is a member of CreativeWork which is not appropriate for your needs.
I have seen this mistake several times where a portion of a schema is selected without regard to the parent element and I understand how easily that can happen. It is a mistake that no one can be faulted for.
What you need to know is that schema types/elements cannot exist without the parent types if you want it to be fully recognized.
At first, the various schema's are overwhelming and relationships hard to understand and how to use the schema confusing and except for the various examples, no-one would likely figure this thing out easily. I get it. The site is good, but not always clear enough even for someone like myself who as worked with mark-up a few times.
In your case, I would be looking at two things: one - the products offered, and two - the business itself. I will begin with the products then the business.
Thing > Product > SomeProducts
I think this one is likely the best. Quoting:
A placeholder for multiple similar products of the same kind.
If that is not quite right, then consider:
Thing > Product > ProductModel
A datasheet or vendor specification of a product (in the sense of a prototypical description).
I am not sure if you are a car dealer or an online listing agent/sales. I did not find anything for online listing agent/sales exactly. But I did find this which may apply:
Thing > Organization > LocalBusiness > AutomotiveBusiness > AutoDealer
It may be that Thing > Organization > LocalBusiness > AutomotiveBusiness is enough if you are an online listing agent/sales.
Remember that as you look at the list above, AutoDealer is nested within AutomotiveBusiness which is nested within LocalBusiness and so forth. You will have to create the nesting of each parent/child type, though you do not have to use elements of any type except for what you actually want to display. As well, while it can be confusing, I believe that LocalBusiness is high as you have to go with the nesting. The examples are scant, and I am hardly an expert though I have done a few to help people. You may need to feel around a bit.
You can use the examples from schema.org as you go to create the nesting. Just cut and paste from the example as you navigate the schema types (eg. AutoDealer) from the top of the hierarchy to the bottom. Once you have done that, include within the nested types the data elements you want to display. Again, you can cut and paste from the examples and edit the data as you see fit though examples do not exist for everything.
You can test your work using http://www.google.com/webmasters/tools/richsnippets
Be patient. This is tedious work as you figure out what needs to be done. Start with the simplist and work outward from there. That way, you know that this bit of work is okay if you get an error. The whole schema thing can get a bit fiddlie. Sometimes it helps to create a relatively blank HTML page and put your code in it before testing. It seems that the tool likes that better sometimes.
Clear as mud? If you need more detail, let me know and I will edit this answer to help make things a bit more understandable.