That kind of information won't be more available here in this forum than anywhere else via rumors on the internet. Your best option is to weigh what is available now and how it fits your needs and budget. The great prices for the T3i and T4i this week should be great motivation to buy sooner rather than later.
There will always be another new camera being released. Once the T5i is out, you'll wonder when the T6i is coming out. http://www.sansmirror.com/newsviews/live-in-the-present.html
That particular line of cameras (xxxD) tends to get updated about every year. You figure we had the 450D in 08, the 500D in 09, the 550D in '10, the 600D in '11, and the 650D (T4) released in '12. Judging by precendent I'd say sometime within the next 10 months. However, I wouldn't hold my breath over it. The sensor has been pretty much the same for the past 3 generations, and you can pick up a good T2i for cheap. Just remember that by the time the T5i is announced and released, we'll be closing in on the release of the T6i. 😉
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.