There's three. All are very user friendly and easy to use.
All three are very well done by good coders who have thus far supported their modifications. Personally, I use the MGC Chat Box as it has all/most the features I want/need plus more, and the ones it does not have are on the to-do list for the mod. I suggest you do the same, and compare all the viable options and see which one best suites your needs, as all of them are very good, and as long as you read and follow the instructions which are written quite clearly and straight forward you really shouldn't have any problem installing either one of them.