The Genome Informatics group is organizing projects for the following:

• Galaxy
• Generic Model Organism Database (GMOD)
• GBrowse
• JBrowse
• PortEco
• Reactome
• SeqWare
• WormBase

You can find more details (including contact information if you're interested in proposing or joining a project) on the GSoC page on the GMOD wiki.

The list of accepted projects for GSoC 2013 has been published. Unfortunately, you won't find your favorite OBF projects on that list this year. I've made a list of accepted projects relevant to bioinformatics for those interested (there may be others):

• Crowd Sourcing Biology at the Scripps Institute
• Dept. of Biomedical Informatics, Emory University
• NESCent (National Evolutionary Synthesis Center)
• NRNB (National Resource for Network Biology)
• SciRuby (Ruby Science Foundation
• SHOGUN (Shogun Machine Learning Toolbox)
• Bioconductor

In addition, it appears that the previous post by girlwithglasses is very accurate, as there are a number of GMOD projects participating in GSoC. The window for submitting student applications opens April 22nd (just under two weeks).

I don't know of any hosts that have definitely applied but I'm sure there will be a number of bioinformatics / computational biology projects in GSoC 2013.

There's usually a short (<2 week) application window in March / April, so I wouldn't worry about it for a while. The site template is empty at the mo.

edit: Here's last year's timeline.