1. Twitter Karma
I think this one is the best for what you want.. Twitter Karma!
As with most 3rd party applications, you will need to supply your name and password as Twitter Karma needs to see who’s in your friends/followers list.

You will be able to see who is following you or if are You following them etc. You can also see how long its been since they have tweeted.

If you Pop on down to the bottom you can make your decision:

If you’re looking to drop everyone, do a “check all” and “Bulk Unfollow” and it’ll go through and unfollow them.
If you just want to follow certain ones, then check the boxes.

A bit of warning, this may take some time, so please be patient.  I find the best way to keep up on whether it is working (Because it goes into work mode the instant you click it: Would be to go to your twitter homepage, and watch the numbers increase/decrease appropriately.

One of the nicest parts is it will show you when they “Last Updated” so you can feel better removing people who haven’t updated “Ever” or “not in a year” or so.

2.Friend or Follow!

It’s actually very simple to use but a little tedious.  Simply browse to their site, enter your name hit submit and you’re off!

At that point, you can click on their names and decide if you want to continue following them or not.  It’s a useful way to see who it is that you are following who is not following you.   But the benefits don’t end there!

Simply by clicking on Fans, you’ll get a list of people who are following you, but YOU are not following back!

This happens to the best of us, or they’re spammers which haven’t been removed yet, in either case you can click on them and choose to follow or not!

Here is where it gets tricky.   Let’s say you chose to follow ‘x’ number of folks and they’re not reciprocating, and you decide  to unfollow them, you need to open up each of their profiles. I like some things about this site but it is not my favourite…it can be very tedious.

3. Untweep
This is a very simple site to follow and if you just want to purge your list according to how active some people are on your list, then you can use this site. Not much to it really…

So remember, if you’re looking to mass follow, mass unfollow, or take any kind of mass actions (Or even just get a feeling of how unbalanced things may be)  – The three tools mentioned above will help you achieve that!

Most of the backgrounds you see with images and information on the left hand side in the background are generally created in an image program such as Gimp or Photoshop, and then uploaded as a background image. The trick in this method is that you have to have the image scaled to fit correctly in the twitter frame on your computer. You need to remember that everyone uses different size screens with different sized pixels. You unfortunately cannot click on any of these links that are displayed in this fashion. People will need to type them into their browser if they want to go to that page.

I have found some other good resources for creating Twitter Backgrounds.

Check these out too:

The Closet Entrepreneur Lets you know how to use PowerPoint to create a background.

Croncast This will give you specs for creating the size of the image as well as other tips

Presentation Zen This gives a great resource guide to getting quality Stock Photos for your Backgrounds

An example of a Twitter profile creted in Gimp