In general, yes. A dictionary search could compromise WPA encryption if you chose easily guessable words/phrases. But WPA is considered very secure if a good password is chosen. (AES is considered even more secure than TKIP, but either is OK).
See #1. Even if you chose an easy to guess pass phrase, it is unlike your neighbor would guess it -- or that he/she would ever try.
The only way to connect to a WPA encrypted AP is to know and use the same password on the client as is used on the AP.
Sure. The channels on 802.11b and 802.11g overlap, so it is best to separate by 5 (1,6,11). Channel 5 is separated from channel 11 by 6, so is OK. I think it is best to use only 1, 6, or 11. Suppose someone else sets up an AP in your area. He notes you are on channel 5 and your neighbor is on channel 11. He would like to separate his by 5, but can't. If you were on channel 6, he could choose channel 1 for the least interference between each of you.