Low-cost airline easyJet announced a new route between Geneve (Switzerland) and Ajaccio. According to the announcement (in French) 6 flights a week will be available since June 29, 2008 till September 14, 2008 for prices of a one-way flight starting at 39.95 CHF (ca. 25 Euros).
For more direct and indirect flights to Corsica check out an updated page Getting to Corsica by air.