Getting skills when u travel to other campaigns

I just want to know... for example if u create a char in Factions and u travel to prophecies... u must go to every town to unlock all the skills?

No, go to a skill trainer in any town and all the prophecies skills you have unlocked should be available.

And.... how do i unlock every skill from prophecies?

By making a character there and doing the skill quests and buying them. Or bring an existing character over and buy them

A lot of towns have skills from earlier towns. Ember Light Camp has all the non-Elite Prophecies skills.

The real question should be is if you want to get them for free or do you want to buy every skill?

The basic skills needed to play any profession are available once you make a character. However, if you intend to have multiple secondaries the Balth/Skill vendor scenario is best to unlock skills.

If you want to get skills for free, that becomes limited after prophecies. In prophecies, you bought maybe half of your skills with gold and skill points. This worked fine until you had lvl 8s in Ascalon arena with MS and rodgort's invocation, not to mention max armored tanks with elite stances and attack skills.

So, then Factions comes out, and the runner business is nearly shut down, and with it, the ability to get skills for free. Nightfall justed added to what was done in Factions.

So, the short of it is, if you are playing with a core profession(the first six), then prophecies has alot of free skills to get in quests,even after Lion's Arch.
However,if you are playing with characters from new campaigns,then it's cash and carry.