iAnnounce is an extension of Mobile Substrate, now available for free on Cydia.  Once installed it adds the ability to announce the name of the caller who is calling.

iAnnounce does not add any new icon on your SpringBoard. Tweak is compatible with iPhone 3GS and iPhone 4 with IOS 4.0 or later and can be downloaded from the  “Tweaks” category of Cydia through the BigBoss repository .