You can customize the ido group to change Ido functionality:
M-x customize-group RET ido RET
or customize a certain variable:
M-x customize-variable RET ido-xxxxx RET
To modify the key bindings, use the ido-setup-hook. For example:
(add-hook 'ido-setup-hook 'ido-my-keys) (defun ido-my-keys () "Add my key bindings for Ido." (define-key ido-completion-map " " 'ido-next-match))