I would like to add Facebook, Digg, Twitter, and Share (which I guess would send an email link) to a client's web page.
I think I found out how to do this with Facebook; but, I wonder, do I have to go to each site to get the proper code? Or, is there a place where I could get all the code at one time?
I see sites, like newspapers, with a lot of icons like these, and I wonder if they come pre-packaged?
I've seen a lot of sites using this one which lets you do tracking and such as well (at least the last time I looked into it). I personally don't like this one, but I see it everywhere, and I'm the type of person who prefers to do things the long way and code it all myself.
Share this is indeed a common used social exchange service. You can try sexy bookmarks. This is developed for a variety of CMS'es like joomla, wordpress and blogger. I don't know if they've got any single html code you can use.
You can also collect the codes manually. Most used services are digg, facebook, stumbleupon, readit and googlebuzz. All of them have the html codes available in their developer section.
The benefit of using sharethis is that you get analytics on your shares.