For any CDMA iPhone4 owners stuck on 4.2.10 without a jailbreak, the redsn0w beta has just been updated to provide support for a tethered jailbreak, which is great news for the community of users stuck there!
Details and links in our sticky here - http://www.iphoneforums.net/forum/iphone-jailbreaking-17/jailbreaking-methods-iphone-18519/
Details and links in our sticky here - http://www.iphoneforums.net/forum/iphone-jailbreaking-17/jailbreaking-methods-iphone-18519/