cheating-is-good

Best answer as chosen by Asker / Ratings
I swear I answered this question like... A week, or so, ago. It was the exact same question, wording, and everything, it was all the exact same... Weird. Dunno if it was you that asked the question, or someone else, but I'll answer it again :)

If you need a cheat, or code, then go look in the Cheats, and user-submitted-cheats section of Grand theft Auto Vice City, you might find the cheat that you need, and some extra ones there.

Shadow Cast

Best answer as chosen by Asker / Ratings
With the PC version, (which you must have, by looking at the title) you can skip missions using a trainer.

Trainers are basically like a source of cheats "injected" into the game and are handy to use (they also don't increase the risk of corrupting your game when cheat codes are entered). Though, even with the best trainers some missions aren't "skippable" and you'll just have to do them to progress. Trainers, by the way, can be found all over the internet especially in the GTA cheat fansites.