Fastinit is a proprietary and much simplified init(8) replacement written by Asus to help the Eeepc to boot faster. Finit is a fastinit reimplementation based on fastinit system calls with gaps filled with frog DNA.
Finit's purpose is to build upon the general workings of fastinit and improve/optimize it for Xandros or alternative distributions running on the Eeepc. Finit comes in three flavors: finit is a replica of the Asus fastinit, finit-mod is an improved drop-in replacement for fastinit, and finit-alt is a generic replacement for other systems. Finit-mod and finit-alt were much improved with patches from Metalshark.
Finit-alt currently supports Mandriva 2008, finit-mdv is finit-alt.c built for Mandriva, and experimental support to eeeXubuntu is being merged from smurfy's port. Patches and reports welcome, send them to firstname.lastname@example.org. The fast, albeit dirty and somewhat unstable jumping car picture was taken by finit-mdv test pilot Ednilson Miura (and patched by me).
Semi-stable packages are released infrequently, and (with some luck) they'll work as advertised. You can find them here.
Bleeding edge versions can be pulled directly with git clone from one of the following git trees. These tend to be much better than the packaged versions (except when they don't work).
Can I use finit with Ubuntu/Fedora/Suse/Debian/etc?
Finit-alt is currently ported to Mandriva 2008 and 2008.1. Some customization is needed to prepare it to other distributions. Work is under progress to port it to PCLinuxOS and eeeXubuntu. It has also been reported that it works with Debian, but with no further details (see links in the "Related stuff" section above).
How much does it help?
Total boot time from power button to GUI is given by BIOS, boot loader, kernel, init, X server and desktop environment times. Fastinit/finit only helps with the init stage, and other solutions such as boot booster, customized kernel, X optimizations and slim user environment are needed to further improve boot time.
Can I use finit in my desktop system?
You can, but you shouldn't. Finit isn't a full fledged init and is recommended only for embedded-style systems such as mini-laptops that require very fast startup, and not for general-purpose laptop or desktop computers.
Can I use finit in the ClassmatePC/Cloudbook/HP-2133/MSI Wind/Quanta IL-1/Positivo Mobo/etc?
Yes, as long as you customize finit-alt to work with the distribution, hardware and installation layout you're using. For instance, Intel-based systems may need module intel-agp to be added to /etc/finit.conf, or you may need to change the pathnames of helper applications in finit-alt.c. If you port finit to a different system, please consider sending me a patch.