CodeIgniteris a powerful PHP framework with a very small footprint, built for PHP coders who need a simple and elegant toolkit to create full-featured web applications. If you're a developer who lives in the real world of shared hosting accounts and clients with deadlines, and if you're tired of ponderously large and thoroughly undocumented frameworks
Model-View-Controller Based System
PHP 4 Compatible
Extremely Light Weight
Full Featured database classes with support for several platforms.
Active Record Database Support
Form and Data Validation
Security and XSS Filtering
Email Sending Class. Supports Attachments, HTML/Text email, multiple protocols (sendmail, SMTP, and Mail) and more.