TuxOnIce has a long feature list, including the ability to cancel hibernating or resuming by pressing Escape, image compression to save time and space, a versatile plugin architecture, support for machines with Highmem, preemption and SMP.
The TuxOnIce website (this one) and mailing lists provide support for dealing with issues.
The primary author of TuxOnIce is Nigel Cunningham. A huge thanks must also go to Bernard Blackham, Florent Chabaud, Pavel Machek, Gabor Kuti and Michael Frank along with many others who have tested and contributed to the development of TuxOnIce.
You can get the source packages for the TuxOnIce kernel patch and tarballs for the userui and hibernate script from the downloads page.
Git trees can be found on GitHub.
TuxOnIce is included in all Sabayon flavours.