I need to convert site that I created in SharePoint 2007 into SharePoint 2010. what is the easiest way to do it?
There is no easy way to do it :)
First, take the back up your SharePoint Content database (which contains the site) and restore it to my SharePoint 2010 DB server. But, before you take db back up, your MOSS 2007 must be on SP2
1) Find the content Database; These are listed under Central Admin->Application Management->Site Collection List
2) Backup the content database, You could alternatively detach it, and copy it. Just doing a backup in SQL Server Management studio is easier.
3) Restore content database to new server, Copy the BAK file to new server. Create an empty DB in Management Studio, restore from backup, you may need to change an option in the "options" tab of the restore dialog to get it to work. (Overwrite db).
4) Create Web App on SharePoint 2010
5) Remove Content Database from the new web app.
6) Run Test-SPContentDatabase on new content database and web application
7) After a successful run of step 6, run the stsadm -o addcontentdb -url
Then Go to the site setting of new site collection (/_layouts/settings.aspx), Click “Visual Upgrade” under “Site Collection Administration” -> Click upgrade link.
8) Run ISSRESET from command prompt
If your 2007 site use some web parts which not installed on the SharePoint 2010, you will meet the problem to open the default page. You can use SPD to create a new default page and right click to set as home page.