I was thinking about selling ad space on my site but I am not sure how much unique visitors etc you should have before people would buy it.
do u have a counter (that gives you detailed info) ? you can use that as your advertisement.. then let whoever wants to buy your ad space to suggest the amt he is willing to pay. -------------------------------------- click here for free ebooks
for ads placement you should have minimum of 50-100 unique/day,and yea also depends upon niche,if its a good niche people will buy you ads.
If you use AdBrite.com, I believe they can automatically price the adspace on your website over a couple of days.
well I am with google analytics and lately have been getting at least 100 uniques visitors a day. My site has tutorials mostly for flash but I have some HTML ones, when I stop being lazy I am going to do some PHP and maybe photoshop ones.
I think the basic rule is this - the more visitors, the more you can charge. It can't hurt to try selling your space. TextLinkAds and AdBrite would be good places to start.