I see this site and other sites have articles but how do I get articles for my site?

You mean the actual articles, or the ones that point to other sites?

For the former, then you just write them yourself or you can pay people to write them for you. If you post on SitePoint in their marketplace or on WebHostingTalk you can probably find someone to write an article for you very cheaply.

For the latter, you can use the vBulletin RSS Poster bot to fetch feeds from other sites and post them automatically. For example, use the feed from SitePoint and use the bot to post on each new article. This is a great technique to increase the amount of content you have. All you need to do is find a site with similar content and an RSS feed and you have instant relevant content for your own site :)

There are plenty of sites with free content that allow you to add all or part of their articles to your website as long as you include a copyright. You can also look on other sites and maybe include a brief summary of an article, and a link to their site. Your site recieves members because people can find valuable content and resources in one location (your site).
Make sure you look at the legality. 'Fair use' (the US law) is kind of sticky as to what you can and can't copy and use elswhere. Fair use is kind of vague, but your best option is to get content that you may freely display in it's entiritiy. As I said above, you can also include a small portion or a summary of an article, and link to the original one with the authors name. I doubt many would object to this at all. Here's a ton of stuffon Fair Use, but most of it is a legal mess ;)
http://en.wikipedia.org/wiki/Fair_Use

As Chroder stated, custom content is also useful - there's plenty of freelance writers out there who are capable of writing whatever content you need (this costs $$$, unlike the first mention). I personally do freelance writing as a hobby for some extra cash - make sure you look at a writing sample, and professional references before hiring though. Some writers are simply looking for cash and you could in fact do a better job yourself. ;)

I would reccomend looking into freelance writers. The market is saturated with people willing to write for pennies, but you would have to ensure quality. If you can afford it, I would pay someone you can trust to write weekly articles over a long-term period.

Most online writers would be easily recruited to write articles for you, or you could go the other route and write them yourself although it might be more trouble than its worth.

I would go to digital point forums for article writers there are tons of them there, and all right good articles for ussaly cheap prices or you could go with fair use

Just one point, there are freelance writers that not only write the articles, but also post them to a lot of places. I suggest to you to look for these ones as they will save you a lot of headaches.

Go to a webmaster forum, search for one on google, and go to one of their buy/sell/trade forums and then there should be a sub-forum like services and post you would like to buy articles, people will usually charge 0.01c/word.

You get free articles from Article directory. More than 1000 article directories avilable. Visite and copy articles for reprint.