Lite has been around in various uses for centuries, but in modern English it is mainly a commercial variant of light. It’s used primarily by food companies, and it usually indicates that a product has fewer calories or fat than a comparable product—for example, Miller Lite, Kikkoman Lite Soy Sauce, and Jarlsberg Lite cheese. This use of lite has been common for a few decades, but many companies still prefer light—for example, Bud Light, Newman’s Own Light Raspberry & Walnut Vinaigrette, and Dannon Light ‘n Fit Yogurt.
In any case, lite is not an accepted variant of light in any of light‘s other senses. If you want to be safe, use it only in reference to low-calorie or low-fat versions of things.
Until now, Bachmann has been something of a Palin-lite figure and has often been portrayed as a Tea Party loon. [Telegraph]
The Black Eyed Peas do their robot Daft Punk-lite thing. [Wall Street Journal]
My guess is the Manning Centre wants to justify or legitimize the Harper Conservative Party’s, Liberal-lite, wishy-washy brand of conservatism. [National Post]
Lite might be useful in instances like these, but let’s not forget that light still means of relatively little weight or having little force, and there’s no reason not to use it where it fits.