How can I edit information I have entered into my contacts list, such as birthdays etc. etc.
To edit certain fields such as Birthday, this needs to be done from the Google web site.
You can not edit the birthday field on the phone.
To edit the Birthday field go to http://www.google.com/contacts.
If I change the info on the google site how do I get the change to take place on my phone?
You can wait for the phone to automatically sync. Or you can refresh your Gmail inbox
(go to Gmail, then select settings>refresh) and the contacts will update immediately.