The usual online employment sites are good places to find a contract employee- www.monster.com, www.hotjobs.com, www.careerbuilder.com. These type of sites let potential employees flag whether they will work on a contract basis, of whether they are looking strictly for full time employment. Conversely, the newspaper classifieds are probably not the best place to find a contractor. Typically, people looking for full or part time employment locally look in the newspaper.
There are also sites like www.guru.com that are strictly for contracts and freelancers. You can put your project out to bid to thousands of potential candidates. Then you not only have a large talent pool to choose from, but you can secure a low price. These sites usually work on a bid basis. You describe the position and then candidates give you their qualifications and the lowest price for which they can complete the job. These types of sites also include long-term contracting positions, so you can successfully find people willing to work in any number of scenarios.
This type of site will often offer a 1099 service, so that you can pay the employee through the site instead of having to do the work yourself.