Arabic Pod 101
Arabic Pod 101 is a subscription site that teaches Modern Standard Arabic with audio and video lessons. The site is geared toward an absolute beginner to intermediate level, so if you can watch TV shows or the news in Arabic and miss very little then this site isn't for you. This site is good for those starting out in Arabic. Their native speakers who read the words and sentences for you are Egyptian, so some of the things they say have an Egyptian flavor to them, but it is still definitely MSA not dialect.
One thing I found very helpful about this site is the 2000 most common word list. It's not just a list of words, how they're spelled, and what they mean. They also have someone say the word and a few sentences to give you context on how the word is used. Seeing and hearing words used in context is the best way to learn a new language and I wish I had this list when I started learning Arabic. You can also have a word of the day sent to your email address. I've been doing that for a while and there have been a few I didn't know, like today's word ردهة الفندق (rudhat ulfunduq) - hotel lobby. I had never seen the word ردهة before. They have audio and context for the words of the day as well.
They have a free 7 day trial going so you don't have to pay anything to see if Arabic Pod 101 is going to be useful for you. If you decide you like it they have 2 different subscription options. The Basic option is $4/month and the Premium option is $10/month. Both options give you access to all the lessons, but the Premium subscription gives you some extra perks like access to their vocabulary videos where they give you a picture of a thing or an action, have someone say the word, and have the word written. It's a good way to pick up vocabulary. The Premium option also gives you access to the list of the 2000 most common Arabic words that I mentioned.
For their free trial, go here.