The issue is serious enough that Facebook has an entire page devoted to just phishing attacks: Phishing Fraud Page

To understand some of the more overt scams, have a look at these excellent articles:

The facebook password reset scam
This scan tries to trick people into giving their password through email links. You can read more about the: Password Scam.

Avoiding it is as simple as remembering that Facebook does not need to send you an email to reset your password!

The facebook antivirus scam
There are scams that now target unsuspecting users by offering products and services that are fake and link off to trojan applications. This particular scam tries to get you to click and install a supposed "anti-virus" software that is not from Facebook, but instead from f'acebook (note the apostrophe). Avoid this by ensuring that you never install ANY application unless you absolutely know and verify it is indeed from facebook.com. You can learn more about the: Anti-virus scam

Gandparents scam

This scam is quite complex in that someone targets an individual to get information and then uses that information to target relations to that person by posing as them. They gather details about you so they can then identify your family. Once you allow them to your friends list, they gather personal details and target someone you know and is close to you (in this case parents or grandparents) pretending to be you toto scam them for money. The scam works because people do not understand that others can impersonate you rather easily. They simply pressing Accept Friend Request to someone who is an impostor. Just pressing the accept button is a very bad habit. Always check to ensure that the person you are adding as a friend is ACTUALLY A FRIEND or associate and not a disguise.

In hopes of avoiding this scam among others, here are some tips on identifying facebook scammers:

1. The scammer's friend request shows up out of the blue.

You didn't make the inquiry to find this friend, and you only have a vague recollection, at best, of the person. So, why do you want to be in touch with someone who you didn't wish to contact and you barely remember? Okay, even if you do, you should be extra cautious when getting friend requests rather than making them. This is especially true if the following characteristics are also present.

2. Friend photo is missing or does not seem to match reality.

I received a recent friend request from a woman named Susan. Her photograph was of a woman in her mid twenties. Yet her autobiographical data indicated she had graduated from university in 1987, which makes her around 40. I know there are miracle creams and cures but few of us can so utterly hide our aging that we actually look early 20 when we're 40. On the other hand, even if it is so this information coupled with the next clue makes it pretty obvious this is a scammer not a long lost friend of mine with magical youth potion.

3. This person is associated with odd interests

Often scammers include various interest groups in their profile to seem legitimate. However, these interests or groups are often not at all in the same location or relevant to the person. In my instance, the scammer is registered with an association located in New York, belongs to a health fitness club in Ontario, joined a sports team from Florida, and her profile says she lives in Michigan. More importantly, no information in the profile relates to me or how this person could have met me (either in Virgina during Univeristy or in California where I live). So how did I meet this person? This should be a clue there is something fishy going on.

Perhaps she is a frequent traveler, but without some link to where I've actually lived, it is very likely these groups are a cover to make the profile seem like a real person. Again, taking this as a single clue, it might be a frequent traveler. But combine it with the others and it becomes pretty obvious this person is not legitimate.

4. There's only one mutual connection. Although this is not necessarily a useful clue on its own, if the person who just requested to be a friend only has one mutual relationship to you, it is a lot more likely this is a scammer rather than a legitimate social contact or long lost friend. It's easy to find out by simply contacting the one mutual friend and asking who this person is. At the very least it gives you something useful to talk to your existing friend about, and at best you could be saving them from a scam as well as yourself.

5. Only wants to meet your friend I've also gotten some odd friend requests that basically read "I am a friend of so-and-so and was hoping to get back in touch through you." In other words, they don't actually want to be my friend, but use my Facebook to identify and get back in touch with someone associated to me.

This is so ridiculous that even if it is a legitimate person it is just a really annoying way to use the social network. If you can't contact the person directly then don't annoy others to get access where you may not be wanted. On most occasions, such a request tends to be a fairly overt scam.

Finally, in today's scamming climate, please check on a few details BEFORE you hit the accept friend request button. This can save you from some serious fraudulent scamming, or at least to avoid having to read countless dull and insipid postings from someone you are not really sure you care about.