To enable anonymous access in SharePoint 2010 the following steps will need to be completed.
It may look like there is a lot of steps to follow but it will only take a couple of minutes to complete and is actually very simple once you have learned the location of the required ribbon buttons:
1. Go to the Central Administration web application.
2. Select the Manage Web Applications option from the Application Management category.
3. Highlight the web application you wish you enable anonymous access on (i.e. SharePoint – 80) by clicking on the application row from the list but being careful not to click on the link text. This will enable a number of new options on the ribbon bar.
4. From the ribbon bar choose the Authentication Providers button.
5. From the modal dialog pop-up check the Enable anonymous access option and hit the save button.
6. Now choose the Anonymous Policy ribbon button.
7. From the modal pop-up select the required zone and ensure that the Permissions are set to None and hit the save button.
8. Now browse to the root Site Collection of the web application to have anonymous access enabled.
9. Select Site Settings from the Site Actions drop down menu.
10. Select the Site Permissions link from the Users and Permissions category.
11. From the ribbon choose the Anonymous Access button.
12. From the modal pop-up select the level of anonymous action to be granted (i.e. Entire Web site) and hit the OK button to save.
Anonymous access should now be enabled.