OpenSource, Emacs IDE with Cedet and ECB

Power up your emacs with Cedet(environment) and ECB (code browser)

(load-file "~/cedet-1.0pre6/common/cedet.el")
(global-ede-mode 1)                      ; Enable the Project management system
(semantic-load-enable-code-helpers)      ; Enable prototype help and smart completion
(global-srecode-minor-mode 1)            ; Enable template insertion menu


Make sure you add the install directory with (add-to-list) for ecb.
(add-to-list 'load-path "/usr/local/share/emacs/22.3/site-lisp/ecb")

Read the README for your distribution. FreeBSD for example,
/usr/local/share/doc/ecb/README