To enable anonymous access in sharepoint 2010 site.
Go through the following steps:
Open the Central admin site of your sharepoint server , click onApplication Management> Manage
WebApplication.
Now select Your Web Application which you want to enable anonymous ,
Click on Authentication Providers, Click checkbox selected for enable anonymous access
Now click ok, then click on anonymous Policy icon in ribbon in central admin site..
Select Anonymous User Policy , I selected none for my purpose…
Now Open Your web application, go to site action menu, site permission,
Click on Anonymous Icon in Ribbon, Then select the Entire Site/Lists as per your requirement , click ok
Your site has been enabled with anonymous access….