"After his last setback, the mad scientist, Dr. Eggman discovers a new energy source he wants for his next scheme located in another dimension known as Equestria. So when his dimensional jump drags Sonic the Hedgehog and Tails the Fox along, It's up to them and 6 friendly newcomers to stop the mad scientist's evil plans and save the kingdom before it's too late."
This is the description of the fanfiction on FIMfiction: http://www.fimfiction.net/story/6217/sonic-equestria
This is now becoming a fangame but it is needing a full cast and crew including the following:
-Programmers
-Scripters
-Coders
-Spriters
-Level designers
-Vector animators
-Artists
-Voice actors
Please message me for further intormation on getting a spot in the dev team.