Simulators and emulators help with design, development, testing and demonstration of software, when the actual environment is unavailable or unsuitable for testing. These are particularly applicable for mobile devices, as hardware is not always even out, service contracts and the number of devices to test make them very expensive, and it can be slow and cumbersome to load for each incremental code change.

Though often incorrectly used as such, they are not interchangeable terms, however.

New ones are constantly being added, or replaced, so please help us keep this up to date. Visit the wiki at www.4ourth.com/wiki or contact us with updates you may encounter.

An entirely other class of resources listed here are Remote Testing Labs. I have only used Device Anywhere, so cannot comment on the others, but believe they all work the same way. Actual handset hardware is disassembled, things are soldered to it, and it's strapped to cabinets. You get to press buttons and it goes over a real network, and gives you the screen output. These are all fairly pricey fee-for-service programs, but some operator developer programs give away a few hours for free. Be careful, as they mostly charge per minute connected, not per click or based on activity; disconnect as soon as you are done.

A good place to start is with MobiForge, who has published a useful guide to actually getting over a dozen emulators to run. Many of these are buried under their developer sites, so you may not have even found them. Most have some trick or other to get running, especially if you are not steeped in technical minutiae.

Web-Browsers

Remote Testing Labs

OS Simulators & Emulators

Prototyping / Wireframing

Full Design Suites

Hardware

There are a few manufacturers that offer device loaner programs to qualified developers. I have never done this, so am not sure what "qualified" means, but I suspect it's pretty thorough. You get a current, active mobile device, you can use for a few weeks (Sony Ericsson is 30 days, for example) for free. Designed for testing of applications, to encourage development on their devices. Most manufacturers' developer programs also offer a discount to just buy their hardware as well.