Surrey Satellite Technologies Limited (SSTL) and Virgin Galactic are seeking financing to develop a low-cost rocket system that could be carried on the White Knight Two aircraft, which was recently developed with finance from Richard Branson's space tourism venture.
The new launch system would would comprise two solid stages and be capable of injecting satellites from 50kg up to 200kg into a polar orbit of 400km altitude. The target launch price is quoted here at $1 million, which would be a reduction by a factor of 5 to 10 times on the current launch costs for similar sized payloads.
This video explains more details of the partnership.
The predecesor aircraft, "White Knight", was used to win the $10 million Ansari X PRIZE, demonstrating the feasibility of an aircraft launched sub-orbital space tourism system.