The source claims they are to enter the assembly lines in August, be announced in September, with availability in early October. While we've heard quite a bit about the next iPhone - dual-core A5, possibly a larger screen, 8MP camera and so on - the iPad 3's improvement mentioned so far has only been a screen with larger resolution.
And this resolution is said to be 250ppi now - 2048x1280 pixels would do the trick to achieve such density, for instance - which places the eventual new display on the eventual new iPad coming this year below the 300ppi threshold required for it to be called Retina Display.
The sources have only confirmed that one iPhone will be scaling up production in September/October, no second, cheaper sidekick in the works, unless you count that the iPhone 4 might go down to $99 on contract, when the new model hits, which Apple usually does. The component makers involved are listed as "Foxconn Electronics (Hon Hai Precision Industry), which is in charge of assembling the devices; Simplo Technologies and Dynapack International Technology, in charge of manufacturing batteries; TPK Holding and Wintek, in charge of touch panel modules; Catcher, in charge of chassis; and Largan Precision, in charge of webcams".
While the iPhone part sounds totally plausible, we still can't stomach a new iPad appearing just six months after the iPad 2 was introduced, unless Apple wants to have some head start before Samsung and LG, which are also said to be planning tablets with high-resolution displays. Apple already broke the mould this year, by introducing the Verizon iPhone, and postponing the new iPhone launch for the fall, so anything is possible.