Sega made waves earlier in the year when they annouced trio of there classic games would be getting HD makeovers and today they have given release dates for 2 of those titles. Both Nights into Dreams and Sonic Adventure 2 will arrive on PSN and Xbox Live Arcade on October 2nd priced at $9.99 / £6.49 / €7.99 and on October 5th priced at 800 MS Points. Sonic Adventure 2 will also include Battle DLC on release selling at $3.00/240 MS Points. Nights will come free with Christmas Nights, a 1996 game given away free with the Offical Saturn Magazine
source
Was hoping for details on a steam release myself, but if it is anything like Sonic CD last year I could be waiting till January