Word Map for Emotions

Question

I am looking for a resource similar to WordNet. However, I want to be able to look up the positive/negative connotation of a word. For example:

bribe - negative
offer - positive

I'm curious as to whether anyone has run across any tool like this in AI/NLP research, or even in linguistics.

UPDATE: For the curious, the accepted answer below put me on the right track towards what I needed. Wikipedia listed several different resources. The two I would recommend (because of ease of use/free use for a small number of API calls) are AlchemyAPI and Lymbix. I decided to go with AlchemyAPI, since people affiliated with academic institutions (like myself) and non-profits can get even more API calls per day if they just email the company.

Answer 1

Start looking up topics on 'sentiment analysis': http://en.wikipedia.org/wiki/Sentiment_analysis

Answer 2

The are some vocabulary compilations regarding affect, aka dictionaries of affect, such as the Affective Norms of English Words (ANEW) or the Dictionary of Affect in Language (DAL). They provide a dimensional representation of affect (valence, activation and control) that may be of use in a sentiment analysis scenario (detection of positive/negative connotation). In this sense, EmoLib works with the former, by default, but may be easily extended with a more specific lexicon to tackle particular needs (for example, EmoLib provides an additional neutral label that is more appropriate than the positive/negative tag set alone in a Text-To-Speech synthesis setting).