There has been no next events for Arceus announced for 2010.
in 2010
The Arceus Event is coming out Later in 2010 for the UK The date has not been annoced!
In Japan in December 2010
You can either use an action replay or you could have attended the arceus event in 2010.
Any time you have arceus in your HG/SS party and go to the ruins then the event will happen!
Jan 16 2010
2010/2011 In Australia and other countries.
12th Pokemon movie in 2010
LugiaHo-OhSuicuneEnteiRaikouArticunoZapdosMoltresMewtwoKyogreRayquazaArceus(event)Giratina(arceus event)Dialga(arceus event)Palkia(arceus eventLatias
You can't you need to get it in the 2009 event or get arceus in trade or mystery gift
i don't think they will make a another event , events are a one time thing