Cosmos ® Black Cable 3 Ft USB Charge and Sync Data Cable + Dock Connector Extender Extension Cable for Ipod Touch Iphone 4 4s 3 3Gs + Cosmos Cable Tie
Edit: So far the product is holding up well.  The extra USB adapter has also worked and lived longer than other off brand clones, and it is pretty much free.  Also I use a Iphone 4S in Otterbox Defender and also some slim cases from time to time and it has no problem attaching with the case.  I was skeptical seeing the reviews other cables got, and considering this is about a third of the price it seemed almost certain to fail in some way.  I was pleasantly surprised.  I use this in conjunction with [[ASIN: