Are there any tools availible for tracking users clicks on a website, both internal and external? Preferably one that is free and can track a series of clicks from a user (Example, user clicked 'blog' then 'archives' then a particular article)
Some server side tools:
If you are looking for free Google Analytics is your best bet. It not only gives you a what links where clicked on by name, but it also gives you what links were click on the page using a simple heat map. I say simple because it won't tell you where on the link that the user clicked on each page, just what % of the clicks on each link on a page. It doesn't matter if the clicks are inside or out I believe.
If one you want something more complex, then you will need Crazy Egg or Kiss Metrics as Thorn007 stated.
I recommend open source (PHP - based on Zend Framework) web analytics Piwik. It is now at version 0.8 and recently get server side tracking API so you can still track those who use noscript or old mobile phones. It's also plugin based so you can explore the list of available 3rd party plugins or build your own. It does click tracking but may not present it easily enough for you, so maybe you do need to write your own plugin for this (don't forget to share it though ;)
If you don't mind spending some money then I recommend getclicky