This is CII (CodeIgniter Installation). I've created this based largely off the fuelPHP and Java Play! framework installation script. 

To use this script you just need to get it from the repo and install it into your PATH anyway you choose..then all you have to do is goto your www directory and type ./cii.sh 

It will give you a list of options
1) Install (This option will install the latest(2.0.3) version of CodeIgniter)
2) Install version (This option will let you choose the version of CodeIgniter you want to install (2.x and up))
3) Install w/sparks (This option will allow you to choose the version as well as install sparks (getsparks.org))
4) Quit (obvious)

From whatever option you choose just follow the prompts 

TODO: or better what I WANT to do...
add support for installing sparks from within the script ...IE 
give a list of sparks to install during CI installation and it will install those sparks as well as the sparks manager and CI.
add atleast basic scaffolding support..IE create a DB/tables/fields and create the models for codeigniter 


Why did I create this? 
Because I'm lazy and I got sick of unzipping or untarring the files to a directory I created etc etc..now..I type cii.sh, choose option 1 - 3 and it's done...