Plagiarism in universities has always been a difficult problem to overcome. Various tools have been developed over the past few years to help teachers detect plagiarism in students' work. By being able to categorize the multitude of plagiarism detection tools, it is possible to estimate their capabilities, advantages and disadvantages. In this article I consider modern plagiarism software solutions, paying attention mostly to desktop systems intended for plagiarism detection in program code. I also estimate the speed and reliability of different plagiarism detection systems that are currently available.