iOS: The newest version (currently beta 3) of keyboard replacement app iSwipe adds new and improved visual cues to make the swipe-to-type keyboard more accurate and easier to use.
If you haven't already installed iSwipe (formerly Swype for iOS), then we suggest giving it a try. When we first looked at the app, we noted that this tweak was a great addition to the iPhone, but that it was missing a few features that make the Android counterpart so good (namely, the lack of the blue "tracer line" and incompatibility with third-party apps).
The third beta fills in a lot of what was missing the first time around, including the tracer line. The tweaked keyboard is also now compatible with more than just built-in iOS apps. I've yet to find an app that the third beta does not work with.
The third and perhaps biggest new feature is the alternate word suggestions bar that appears after finishing a word. Most of the time the app will predict the right word, but this bar lets you easily select the correct word if iSwipe didn't get it quite right. If you were waiting for iSwype to mature, than that time has arrived.