So GStreamer is not an official Google Summer of Code project this year, but that doesn't mean you can't to a GStreamer releated summer of code project. In fact there are many GStreamer releated projects available through other participating organisations such as GNOME, KDE, Mono, Xiph and ffmpeg to name some, where your contribution would directly or indirectly benefit GStreamer.
So if you are interested in doing a project around GStreamer you can check
out the idea pages for these organisations for some of the ideas available:
Organisations listing GStreamer using projects:
GNOME:
Since GStreamer is the multimedia framework of choice in GNOME there are
many possible projects under the GNOME banner using GStreamer. Check out
the GNOME ideas page
for some of the current proposals or add your own.
KDE:
KDE is currently working on their multimedia framework abstraction
layer called Phonon and there should be able opportunity to do GStreamer
releated projects around this or work on projects such as Amarok. Check
out the KDE
ideas page for some of the current proposals or add your own.
Mono:
There are already some major Mono based applications using GStreamer, like Diva and
Banshee. If you want to do a
multimedia application using Mono or C# there is probably a good chance to get it accepted under
the Mono banner. Check out the Mono ideas page
for some of the current proposal or add your own.
Xiph.org:
The Xiph.org foundation is a critical provider of libraries and technologies, like Ogg, Vorbis and Theora, for GStreamer and are listing many projects on the Xiph ideas page which have a strong GStreamer element in them.
Other projects:
There are other projects taking part in the Google summer of Code
which you could try approaching with proposals. Creative Commons is one
we mentioned earlier, but maybe porting MythTV to GStreamer, Ardour GStreamer
integration, Gaim farsight integration,
or some distribution integration work for Debian, OpenSolaris,Ubuntu,
FreeBSD or NetBSD. Creating GStreamer plugins for OS specific stuff like FreeBSD TV capture for instance could be a project.
Be aware that these suggestions are ours, so you need to check with the projects involved if you would be allowed to do a project combining GStreamer with their project as your SoC project.
Most of these organisations would be willing to take on projects of your own making too, so even if you don't see your dream project already suggested you should feel free to contact the organisation in question and ask if you could do your project under their banner. For instance GNOME, KDE and Mono, and maybe Python might accept your 'GStreamer' project if it also involves their technologies, for instance by doing the GUI in GTK+ for GNOME or Qt for KDE. Or if you want to do a tool that enables proper tagging of all kind of media with the correct Creative Commons metadata then the CC might be willing to let you do that under the Creative Commons banner.
Also a lot of possible projects could fall under many different projects so you should evaluate which projects are most likely to approve your project. Lets say you want to do some work on the Pitivi non-linear video editor. Its writen in Python, its used GTK+ and it uses various GStreamer plugins to enable its codec support. So depending on what you wanted to do you could ask the Python project if they would be willing to let you do it under their banner as it could be a Python killer app, since it is using GTK+ you could propose your project to be done under the GNOME project as it is a project that promotes GTK+, if you want to add support for editing a specific format you could maybe do it under the Xiph or ffmpeg projects. Or if you want to enable Creative Commons metadata addition and editing with Pitivi you could do it under the Creative Commons project, or if you want to do a Qt/KDE frontend you could maybe do that under the KDE project. Of course all depending on approval from the respective projects. Point is that be creative and remember that it never hurts to ask.
The GStreamer community are willing to help out with providing mentors no matter which organisation you do the work under, so if you have such a project and need a mentor with GStreamer skills come to the #gstreamer IRC channel on irc.freenode.com or send a mail to the GStreamer-devel mailing list, or even mail a specific developer directly if you know who would be a good mentor for your project.