Today with laptops and wifi being the standard in almost every restaurant, coffee shop and bar across the planet freelancing is become a viable option for getting a full-time income while working a flexible schedule. Below are some great sites that can help you find supplemental work whether you're looking to work full-time, part-time or just occasionally (freelance).
Below are some great sites to help you get started:
Fiverr.com - Geared towards selling your services for $5. You can sell as little or as much as you like. You can sell virtually any service online (your voice, your photo, modeling, web design, graphic design, you name it).
99Designs - Targets more of graphic and web designers.
Amazon Mechanical Turk - This allows you to outsource your work (HIT's) Human Intelligence Task's to other individuals.
Craigslist - One the older and hyper-local sites. The market is primarily USA based and stronger on the West Coast.
CrowdSpring - Marketplace for logo design, web design, and naming.
DesignCrowd - Start a graphic design contest on DesignCrowd. Get custom logo designs or graphic designs from over 125000 professional designers
Elance - Access over 2 million skilled freelancers from around the world. Find rated web developers, mobile programmers, designers, writers, translators, marketing professionals and more!
FancyHands - Fancy Hands is a team of assistants ready to work (you can register to be one).
Freelancer - Similar to Elance.com
Google Helpouts - Helpouts connects people who need help with people who can give help over live video. Get help across multiple topics right from your PC or mobile device
OneHourTranslation - One Hour Translation - Professional Translation Service (you can also do the same on the other freelance sites).
PeoplePerHour - Similar to Elance.com
SEOClerks - Allows you to work with different SEO providers.
TaskRabbit - Similar to Elance.com
Voices - Specifically for voice talent.
Zaarly - Jobs in handy work, House Cleaning and other household chores. Similar to Craigslist but specifically for around the house work.
zirtual - Similar to Elance.com