Spelling alteration is a technique search engines use to help you get better search results. It fixes errors when you misspell something, it can show alternative spellings of words and it can find synonyms of words you are searching for to help get better results.
It seems Bing feels that there is a lot of room for improvement in this area of their search engine as they are teaming up with Microsoft Research to offer a reward to the team that develops the best spelling alteration technique. They are calling it the Speller Challenge and goal is to "develop a spelling alteration system suitable for large-scale statistical data mining-based web search."
A common approach to spelling alteration is the noisy channel model, in which the received query (q) is treated as a noise-corrupted version of the target query (c). In this model, the spelling alteration system alters q into c and returns the latter's results. The techniques to best identify query/target pairs and best estimate these statistics are the active research problem that underlies this challenge. But that's just the foundation. Place the spelling alteration task in the context of web search, and you have another dimension to consider. The effectiveness of using a fixed lexicon is a known problem because it can lead the speller not only to miss "real word" errors but also misrecognize out-of-vocabulary tokens as errors.
If this challenge sounds like something up your alley Microsoft is offering a sample dataset for developers and researchers to use, a similar dataset will be used to test the effectiveness of the spelling alteration engine. There will be five winners with the first prize winner getting $10,000.