Taimur Asad, at Redmondpie.com, offers resetting the phone's "Network Settings" and installing the "Push Fix" app from Cydia, a replacement packing and installer program along with a catalog of apps for jailbroken phones. "I found out that installing this app also fixes all issues caused by blacksn0w related to WiFi, Youtube apps and GPS along with Push Notifications on hacktivated iPhones" Asad writes. Hotz, on his blog, says he hasn't run into Wi-Fi issues himself, but promises to investigate them if someone figures out a way to replicate the problem.
Full Article at PC World