Today, Machine Translation is a useful tool if one does not simply try to replace human translators by computers. There exist useable commercial systems and there has already been large-scale success. But all these successes in MT were based on thorough analysis, practical evaluation of demands and thoughtful application of available means, not marketing descriptions of inferior products.
Yet, there is no system keeping the promise of instant, accurate translation from language X to language Y. Pre- and/or postprocessing is always neccessary and, depending on the purpose of the translation, should be done by an able translator.
To get a rough overview of the contents of a document in a foreign language, some products might suffice. But usually it makes more sense to follow the machine aided human translation approach, that is the human translates and uses the computer's facilities to look up words, idioms, synonyms etc.
For special tasks, human aided machine translation can be used to reduce costs. Again, sound analysis is neccessary as the texts to be translated must be suitable for MT -- just installing "some" software will not do it.
I agree with Jeanette Pugh:
From the human translator's perspective, MT has gradually become more of an ally than a threat.
[Pugh 1992, p. 18]
I only covered text-based MT here while translation covers more than that. There are promising projects, for example speech-to-speech translation in realtime like Verbmobil9, needing completely new techniques and provoking new approaches which might lead to improvements in text-based MT as well.
Another feature [of Verbmobil] is the presence of a special dialogue management module keeping track of the course of the dialogue. In several places, considerations about human interpreting strategies have found their way into the system modules. This tendency increases in the second project phase [...]
These characteristics make the Verbmobil a typical representative of the new tendencies in MT. It is, however, only one of several interesting examples. The efforts of many other researchers are going into the same direction [...]
[Hauenschild, Heizmann 1997, p. vii]