I was hesitated to write this article: helping someone hack or cracks someone else's site is way too unethical. I hope you won't use this article to do this. Instead you can use it for security check on your sites or scripts.
You will need basic skills in SQL and PHP/ASP/JSP to understand the following technique, I will do everything in MySQL and PHP.
Generally, SQL injection is a beginners and professionals methodolgy of cracking into a web application. SQL injection doesn't depend generally on web server, SQL, script bugs. Instead, it depends on human bugs: bad coding and lack of symantec checks from the developer's side.

Some long time ago, I decided to move from simple text editors (mine was Macromedia Dreamweaver) to an Integrated Development Environment, aka IDE. I have so far tried some good number of IDE's (or software that promises to be so) and text editors. The major problem with IDE is system resources, a normal IDE will kill your 256MBs Ram machine, a good one may not feel comfert with 512MBs of Ram dedicated to it! After spending some enough amount of time with each one, I think it's a good time to give credit when credit is due: Zend Studio: 8/10 Pros:

Autocomplete for PHP built-in functions and your own functions, variables in your current scope (this is a good one).

Recently I had the opportunity to attend a seminar about Ruby on Rails, things were nice with Ruby and Rails, I liked scaffolding, I also liked the various features of Rails and I think it's the real power of RoR. Afterwards I deceided to put Rails versus Cake PHP, a PHP framework that works on all recent PHP versions from 4.3.2 till 5.0 (I haven't tested it on PHP 5.1 but I think it will need some hands-on work to have it error-proof). I started by creating a simple e-commerce database-driven site with them both and overall result I get is: I really see that Cake PHP is a PHP version of Rails.

I tried installing Ruby and Rails on Ubuntu 5.10 (Breezy), I followed exactly what was written in the article: http://fo64.com/articles/2005/10/20/rails-on-breezy But I ran into trouble with Rails after the installation, Rails said: "Rails does not work with Ruby version 1.8.3". After some search and a friend's help, it appears that you have to do the following BEFORE you follow what's in the article:

Since the lauch of PHP3, many things has changed. PHP is now dominating (according to NetCraft), with some great number of projects created everyday on SourceForge and FreshMeat, still I see a problem with PHP developing: PHP was not built for developers. PHP was built for designers and programming newbies, maybe this helped many snthausiasts to join the developing community, but it, for sorrow, convinced some PHP developers that what they do is correct which isn't the case usually. This is, IMHO, the point that sets ASP.NET in a higher rank against PHP: it was built for developers and it's a real programming language.

Since I started to read the news about PHP5, I was happy that Zend has finally deceided to bring us some real OOP to the world of PHP, regardless whether the OOP approch in PHP5 is what really we all wanted or not, still a good step I see in PHP5. The major problem with PHP5 was its bad backword-compatibility with PHP4; forget about PHP3; thus major PHP scripts specially open-source mostly faild to work on PHP5 environment. The reason I saw behind this failure was mainly in the pass-by-reference since PHP5 passes by reference while PHP4 passes by value (which is extremely strange thing). Anyways, I; like many PHP coders; started to gather news and stuff about PHP5: what's new, how to convert current code, and so forth. I do not think I was that late to do this but after I was OK with all the new stuff in PHP5 I suddenly read in the news about PHP6!!