I've noticed this only started happening after jail breaking the other day (mind you I've had my phone a week or maybe a little more only). But I also see some people complaining about it in the iPhone 4S forums.
I get wifi cutting out for a couple seconds every now and then when using the iPhone in my room, it interrupts running programs and such. Kinda annoying.
Is anyone else experiencing this specifically because of jailbreak? Or did you have this while running pure? Also, if it's a jailbreak issue, not an iPhone 4S issue, is anyone with iPad 2 experiencing this?