[Bungleau]

You're most welcome, Javrix.

If you look at the manual, the description of the different classes tells what basic skills they can acquire (or not, for that matter). For example, it says that wizards are limited to daggers and staves. Once you learn a skill, however, you can continue to increase your level in it. So if your warrior learns sword, he can continue training in it even if he's a warlock later on. He may not be able to equip the sword, but he can train in it.

As for other skills, the Best Tips thread is your best place to go. Any skills and traits that you can pick up later on are described in there, at least if we've found out how to get them.