No chance in hell.
Online gaming was free for years before X-box Live (except for MMOs which have server costs). I don't understand why people actually accept they need to pay when only one service charges for such a basic function. As a consumer it seems backward. If Sony start charging just to play online then I simply won't play online on Playstation products and all online gaming will be done on my PC.
Personally I hope to see a more PC-like online service on PSN with clan servers and more control to users to offset their own server costs.