I agree with kingbred, it is a very complicated language. The best way to promote anything is to advertise it. The cheapest way is by word of mouth in forums, chats, games, etc, plus it's free. What kind of forum?
Well it depends what kind of site you want to make. If you want to make a forum I recommend vBulletin, if you want to write a blog then wordpress, or you want to make a shopping site then CS-Cart. I use all of these, they're all good SEO wise and are easy to work with. If you want to do some custom work, and you want it to look pro, I would use elance or rentacoder. If you just want to learn PHP, I'm actually learning right now by free php tutorials here: http://www.w3schools.com/default.asp PHP is fun and can do so much. What do you want to do?
Given that ASP can be written in a Basic language it is much easier than PHP as it is much more "english" for someone with no programming experience to learn. If you are new to it all then dont bother with classic ASP as it is a poor inline script based protocol rather than an object orientated language and so you should go straight into its replacement of ASP.Net. Easiest thing to do is download Visual Web Studio Express 2008 which is a free program for developing .Net websites in and includes a built in debugger and test server (plus you can download a free version of Ms SQL Server too) so you can do all but make graphics in one program. As to learning it, there are plenty of great websites for learning - W3Schools has a reasonable intro, 4GuysFromRolla is very good, www.ASP.Net is unsurprisingly good and includes a number of "starter" applications you can download an customise/ see how they work etc.
Forums are difficult to promote on the basis that there exists the vicious circle of needing active users to attract active users. A lot will depend on what the topic is so you have all the normal options of banners, link exchanges, SEO etc but you can also pay posters to contribute and make the forum seem busier but then you need to ensure that they firstly are going to give worth while contributions and secondly not just copy paste others work which gives you a copyright issue