"Gonna" = going to. This is what we call eye dialect. Eye dialect is the use of nonstandard spellings, such as "enuff" for "enough" or "wuz" for "was", to indicate that the speaker is uneducated or using colloquial, dialectal, or nonstandard speech. You can also call it slang. For example: "I'm gonna kick some butt". "I'm going to kick someone's butt."

gonna = going to It's a way of expressing the future tense. It means something like "I will" or "I intend to." Example: I'm going to run to the store. [I will go to the store./I intend to go to the store.] I'm gonna download iTunes. [I will download iTunes./I intend to download iTunes.]

gonna is a slang word of "going to" which has a future meaning like "I will" or " I have to"... Example: Im gonna attend a wedding on saturday or You can say it " Im going to attend a wedding on saturday. The word gonna has a future meaning which describes an special event that will happened on saturday... And I think I am the one who used it when i answered your question. Am I right?

"gonna" is a short form of "going-to"... like I'M GONNA read now it is colloquial, (I've heard that it is mainly used in American English) and informal... so never say to your boss "whats gonna be our next project?"