Y Combinator
Mountain View, Calif.

Paul Graham, an influential coder with a PhD from Harvard, started Y Combinator in 2005. Graham’s claim to fame: selling his software company Viaweb to Yahoo! for $49 million in 1998. In the six years since its inception, Y Combinator has helped launch over 300 technology companies. Notable graduates include Dropbox, a file hosting company reportedly valued at $4 billion, and Airbnb, a booking service for short-term stays at private residences. With the help of veteran Silicon Valley investors Ron Conway and Yuri Milner, every Y Combinator company now receives an investment of $150,000 in convertible debt upon entering the program.

TechStars
National

Started by David Cohen, Brad Feld, David Brown, and Jared Polis in 2006, TechStars operates intensive 12-week mentorship programs in five different cities in the United States. Its founders attract an average of nearly $1 million in funding following acceptance into the program. The fund recently released the Unified Seed Accelerator Application allowing prospective entrepreneurs to submit one form to a network of 19 participating incubator programs.

Excelerate Labs
Chicago, Il.

Sam Yagan and Troy Henikoff know how to build companies. IAC acquired Yagan’s OkCupid for $50 million in 2010 while Henikoff sold his SurePayroll for $115 million in 2011. Together they run Excelerate Labs, a 13-week summer program for startups. Companies receive a $25,000 seed investment in return for 6% in equity. New World Ventures, a local venture capital firm, offers each startup an additional $50,000 in convertible debt. Sessions culminate in “Demo Day” where companies pitch to a room of over 200 investors at the House of Blues music venue in Chicago.

500 Startups
Mountain View, Calif.

A longtime fixture of Silicon Valley, angel investor Dave McClure houses both a seed fund and a startup accelerator under the 500 Startups brand. The accelerator, begun in 2010, invests $50,000 in each accepted company. Companies in the current program include Fitocracy, a website that turns workout statistics into a social game, and Forrst, an online community for software developers. One major perk: access to an international network of 160 expert mentors. (For more on McClure’s seed fund, check out Road Warrior.)

Capital Factory
Austin, Tex.

Capital Factory likes the number 20. Startups accepted into the program receive a $20,000 investment, another $20,000 worth of perks (think legal and web-hosting services) and round-the-clock access to 20 mentors. In return, Capital Factory gets a 5% equity stake in each company. Founder Joshua Baer co-teaches “One Semester Startup”, an entrepreneurship course at the University of Texas in Austin.

DreamIt Ventures
Philadelphia, Penn.

Founded by Steven Welch, Michael Levinson, and David Bookspan in 2007, DreamIt Ventures claims such notable alumni as SCVNGR, a location-based gaming company with over 2 million users, and SeatGeek, a popular search engine for event tickets. The incubator puts up $5,000 for each company, and another $5,000 for each co-founder. It takes a 6% equity stake in return. DreamIt also works with Comcast Ventures to run the Minority Entrepreneur Accelerator Program (MEAP), which funds and mentors minority-owned startups.

Entrepreneurs Roundtable Accelerator
New York City

ERA is the new kid on the tech block. Startups get a $25,000 investment and spend three months at ERA headquarters in Times Square. Recent grad Public Stuff, a software company that helps cities and buildings manage complaints, counts the Burj Khalifa – the tallest building in the world – as one of its clients. One unique perk: American Airlines gives each ERA company 10,000 travel points, good enough for five round-trip domestic flights.

I/O Ventures
San Francisco, Calif.

Offers a co-working space, an accelerator program, and a coffee shop for startups---all under one roof. Founders include veterans of MySpace and BitTorrent. One graduate, damntheradio, which sets up Facebook fan pages, sold to FanBridge, an online fan management service for musicians, for an undisclosed sum in January 2011.

Tech Wilcatters
Dallas, Tex.

Tech Wildcatters brings the incubator trend to a city better known for oil wells than open-source software. Founder Jon Feld sold his Navigator Systems to Hitachi Consulting in 2006 for an undisclosed amount. As part of the TechStars network, Tech Wildcatters accepts the Unified Seed Accelerators Application.

AngelPad
San Francisco, Calif.

Founded by a team of former Google execs, AngelPad has launched a total of 37 startups in just under two years. In addition to a $20,000 equity investment, AngelPad companies can get up to $100,000 in convertible debt from two undisclosed venture capital firms. The Fall 2011 session received 2000 applications for 15 slots.