FSL Contains the following seperate executable functionallity:

STRUCTURAL TOOLS
* BET - Brain Extraction Tool - segments brain from non-brain in structural and functional data.
* SUSAN - Nonlinear noise reduction.
* FAST - FMRIB's Automated Segmentation Tool - brain segmentation (into different tissue types) and bias field correction.
* FLIRT - FMRIB's Linear Image Registration Tool - linear inter- and intra-modal registration.
* FUGUE - Unwarps distortion in EPI images using B0 field maps.
* SIENA - Structural brain change analysis, for estimating brain atrophy.

(BET, FLIRT and FUGUE are also used in FMRI analysis)

FUNCTIONAL TOOLS

* FEAT - Advanced FMRI analysis with easy-to-use yet powerful GUI. Includes all necessary preprocesing, model-based and semi-model-free statistical analysis, automatic registration to structural and/or standard space, and fixed- and random-effects group statistics.
* MCFLIRT - FMRI motion correction.
* MELODIC - ICA-based model-free analysis of FMRI (and other 4D) data.