• Linux 2.6 features ("I/O Scheduling" section)
• Choosing an I/O Scheduler for Red Hat® Enterprise Linux® 4 and the 2.6 Kernel
• Linux I/O scheduler (WLUG)
• website optimization tips ("Disk elevator algorithm" section)
• Linux I/O Schedulers PDF, from Hao-Ran Liu
• Interview of Jens Axboe (kerneltrap)

The noop scheduler looks good to use with Flash memories, or maybe with SATA disks and NCQ (Native Command Queuing) enabled.