Case-Mate has released a set of colourful iPhone 3G and 3GS cases that have an extra sleeve for credit cards or I.D. of similar size. While cases don’t usually excite me that much, this seems like a simple, handy addition that could make life easier at work functions where you need to have business cards handy, and night life where fishing around for a wallet is awkward, on top of the standard scratch protection a case provides. Think you could this useful? Pick it up for $29.99.