what are the different type of workflows involved in sharepoint 2010?

Well, that depends how you want to look at. You can classify them as

1.) Declarative and Complied
2.) State and Sequential

Google has a lot of information about them. Go out and look for it.

Here are a few articles, you might want to start with:

http://technet.microsoft.com/library/cc263148(office.14).aspx#Types[^]

SharePoint Workflow Basics[^]