I am a self taught programmer, with no formal degree in CS. I have read couple of papers which were recommended on some or other blog and found them interesting. Where can I read papers on computer science ? Are these papers available for free? If not papers are there any essays on any popular blog posts?
If you have no formal degree in CS, I think what you need is textbook instead of scientific papers.
Being a self-taught programmer is a great achievement and I think you can build up on that with theory. But, reading papers require some deep knowledge in some area.
I would suggest you to buy one of these books:
In these books, you can also find some references to suggested readings.
As has already been noted, papers probably are not the best way for you to start.
Perhaps you might like to check out the ArsDigita University website. This has been a project running in 2000 and 2001 (yes, some time has passed since then, but I think this does not really matter for the basics of CS), providing an intensive introduction to the most fundamental areas of CS. Course materials are available at the website, as well as pointers to books used in particular courses. In addition, lecture videos are also available online.
i´m in your same situation. I've never studied computational complexity formally, apart from some programming courses i did.
CS is a very big area of study and the advice people will give you will depend in your particular interests.
An area of study that doesn´t require (in general) to know much about mathematics/complexity theory is the study of the complexity of games. I've beeen reading papers about it and some them are more accesible than others, but generally patience is the most important thing to understand those papers.
A good place to start is the page of wikipedia: List of np complete problems. Look in the section of games and puzzles and you will see references to papers about game complexity
If you insist on reading papers, you should be able to browse the journals in the library of a university with a CS program (the more engineering-oriented the university, the more likely they will have such papers). As long as you are discreet and don't try to take out anything, you shouldn't even need to be a student or faculty to use the library (I've done this myself).
On the other hand, don't be surprised when what you read turns out to be both (a) very challenging to understand and (b) concerned with issues far outside the range of practical significance.