While it’s true that Android 4.0 Ice Cream Sandwich has been announced, other than the Software Development Kit it hasn’t been released yet.
That means you can’t buy a phone running ICS and you can’t flash a stock or custom ICS ROM onto your current phone.
But, all is not lost if you want your current phone to look like it could be running ICS! XDA-Developer sonnysekhon grabbed the goodies from the ICS SDK and stitched them all together into a nice theme.
If you’re running a ROM that supports the Theme Engine (like most CyanogenMod ROMs and their derivatives do), all you need to do is download and install a single .apk, fire up Theme Chooser, and pick “ICS” from the list. You may get a note that “the theme is missing assets for your device’s screen size”, but you can apply anyway and things will likely work just fine (if not, just select the “System” theme and you’re right back to where you were before).
Find the download links at the source, and enjoy your “almost” Ice Cream Sandwich phone!