How long will it take until someone reviews my article?
An article may take anywhere from a couple of minutes to a couple of weeks to be reviewed, though a few days to a week tends to be a fairly safe estimate most times.
Keep in mind that the review process - and the rest of Wikipedia - is entirely volunteer driven and thus average review times may fluctuate fairly often. Review time is based on many factors including the amount of editors that are currently reviewing, the current review backlog (2,587 as of current - ~400 is a fairly normal backlog), the initial quality of your article, the size of your article and so on.
Do note that reviewers are not in any way required - and often don't - review article's in chronological order of submission, and as a result your article may be reviewed at any one time regardless of the amount of article's currently waiting for a review.
How will i be notified once my article has been reviewed?
Most AFC reviewers use a helper script that simplifies the task of reviewing new article's. If an editor reviews a page the result will be placed on the users talk page. If you are logged into a user account and someone places a message on your talk page, a new message bar bar will appear stating that someone send you a new message.
If you only edit infrequently, or do not wish to log in every day to see if your page was reviewed, you can watchlist use a RSS or Atom feed to keep track of your page (Instructions on how this can be set up can be found here). Alternatively you can opt to bookmark the page and have a look at it ever so often.