1) do Wiccans practice sorcery?
Sorcery: the use of power gained from the assistance or control of evil spirits. No Wiccans do not commune with, barter with, use, misuse, or seek to control "evil" spirits
2) is there a difference between sorcery and witchcraft?
Yes. Witchcraft is a magical practice that uses natural elements and their archetypal symbolism to enhance the power of belief and will by combining and directing conscious and unconscious strengths towards a single goal or purpose.
3) do you have a heaven or hell, or any form of afterlife?
There is no single doctrine regarding what if anything occurs after death. The focus of Wicca is life and the hear and now. A belief in reincarnation in one form or another is common, but not mandated. In general it is not believed that the gods are concerned with reward, punishment or retribution. Actions have consequences and we accept responsibility for those actions, but consequences are naturally occurring and not divinely driven.
Summerland is the most common nearest concept to an after life destination, but it is most often considered a place of rest between reincarnations not a permanent abode.
4) I'm a bit confused as to who you actually worship. It was my understanding Wiccans have a god and a goddess, but I also have seen on the net Wiccans that have patron deities, eg. Bast, the egyptian cat goddess, or Diana, a roman goddess
Wiccans do not actually worship deity. The gods do not demand that we bow our heads, lower our eyes, or demean ourselves or our spirits in their presence. The relationship sought is not a master/slave, king/serf, all-significance/no significance relationship. The gods are honored because they are gods, but they do not demand servility. Sometimes it is believed that the gods offer a special relationship. The relationship of patronage. If you have a patron deity you have a primary relationship with them, but that does not disallow a relationship with other gods.
5) what do your spells do? I have heard a variety of stories, ranging from necromancy to divination
If magical practice is incorporated into religious practice which isn't necessarily a given, it is used for all the myriad purposes that generally are considered a reason for prayer in those religions which resort to prayer for help and assistance. Our "wiccan" gods expect us to be self reliant and self responsible. For those who choose to use magic, magic is considered to be just one of many tools the gods have provided that make self reliance and self responsibility possible.
6) is there a devil or some form of evil archetype in Wicca?
Nothing can be perfectly-good or perfectly evil. Nothing.
7) why do some (mostly monotheists) associate Wicca with their devil?
Ignorance
9) a lot of Wiccans sign on and off on internet forums and such with 'merry meet' and 'blessed be'. Why is this done?
Blessed Be is a reference to the blessing ritual used in many initiation rituals. It isn't meant to be a greeting. Merry Meet is a shortened version of Merry we meet merry we part and merry we meet again. often used in ritual when a circle is opened at close of ritual. It's used like a secret handshake to identify yourself as wiccan to another wiccan. Personally I never use it outside of ritual and neither do any wiccans I know who have been wiccan for any length of time. It seems to be tossed about indiscriminately by new converts as an outward sign of their conversion.