Other frameworks include PhoneGap, QuickConnectFamily, MobileReflex, iPFaces and Rhodes.
In beta (at the time of this writing) is the Particle Platform.
The Particle Platform is an open and extendable cross-platform SDK that automates the porting process, enabling developers to create native applications on all smartphone platforms from a single, manageable code base. With Particle, developers can code in familiar programming languages and deliver apps to every platform.
Appcelerator announced it would release a product, called Titanium+Commerce (available by 1st half of 2011), that will allow 8 million PayPal merchants to build multi-platform mobile apps with a host of features including mobile payments, coupons, social sharing, loyalty programs and product scanning (courtesy: GigaOM). For now, developers can use PayPal’s Mobile Payments Library for easy check-outs.