As much as I would like to see this as well, this is something for the far future - good translations can take up quite some time and resources and bad translations can really cause someone to shun an otherwise great game.
As a negative example I´d put the tutorial of Chivalry: Medieval Warfare here: The localized German version had random bits of text flashing before the line was actually spoken, appear during a blackscreen or stay on screen far too long. It´s about five sentences of explanation and even though the translation was usually correct - if this was my first and only impression of the actual game (mind, it was the tutorial - I was expected to play that first!) - my reaction would simply have been "what an unfinished mess!". The game itself was actually a blast to play and my favorite for quite some time but I bought and played it because I was already accustomed to the awesome Half-Life mod it was based on. Yet my whole impression of the game could have easily been spoiled by a handful of misplaced lines in the translation of the otherwise fully functional tutorial level.
Maybe start with simply translating menu screens and instructions - if you really think you can manage it - and leave the in-game stuff like dialogues and letters alone (just don´t forget to make this clear to potential buyers who could otherwise feel betrayed for buying a only seemingly fully-translated game).
Foreign voice actors would be absolute overkill unless your game becomes a huge financial success (but, c´mon, not even the GTA series does this).
However, given that the translation would most likely be text only, you could be tempted to allow some kind of collective community efford by your, I must say, very loyal fanbase... I am just a bit afraid that this would lead to many parts of the game varying drastically in tone and style due to different translators. Also, I don´t know if you have any means of quality control regarding other languages.
