Several PCB design and Electronic Design Automation (EDA) packages are available for free that provide a great alternative to the premium, full featured IDEs that can run thousands of dollars. Most of these packages include schematic capture, output to gerber or extended gerber formats, and have relatively few design limitations.
ZenitPCB is an easy to use PCB layout program that also includes schematic capture and a gerber file viewer. It is limited to 800 pins maximum in the free version, which limits designs to smaller hobbyist or semi-professional use. ZenitPCB is able to export extended gerber files, allowing PCBs to be made by any PCB manufacturer.
FreePCB is an open-source PCB design package for Windows. It was designed to support professional quality PCB designs but be easy to learn and use. It does not have a build in autorouter, but FreeRoute, a web-based PCB autorouter can be used for autorouting. The only limitations to FreePCB are a maximum board size of 60x60 inches and 16 layers. Designs can be exported in the extended gerber format, used by all PCB manufacturers.
Osmond PCB is a free, full featured EDA package for the Mac. Osmond PCB has no limitations and can even work with both imperial and metric units in the same design seamlessly. Osmond PCB can import a PDF file to serve as a background image, allowing a design to be matched to the mechanical enclosure or trace an existing design or datasheet. Osmond PCB supports direct printing of a layout to a transparency for the toner transfer technique for DIY home made PCB fabrication. Extended gerber outputs are also supported, allowing freedom of choice in manufacturer.
ExpressPCB is a simple to use PCB layout packager aimed at the first time user and designer. ExpressPCB offers a schematic capture program that integrates with their PCB layout software. The schematic and layout files can be linked to automatically carry changes forward. ExpressPCB is meant to be used with the ExpressPCB PCB manufacturing service and does not support outputting to standard formats directly. ExpressPCB offers a file conversion service for a fee if standard outputs are required.
The best open source (GPL) EDA package is KiCad, which is available for linux/unix, mac, windows, and FreeBSD. The KiCad suite of programs includes schematic capture, PCB layout with 3d viewer and up to 16 layers, footprint creator, project manager, a gerber viewer. Tools are available to import components from other packages, such as Eagle. KiCad has a built in autorouter and the freeware FreeRouting can also be used. KiCad supports outputting to extended gerber formats, enabling freedom in selecting the manufacturer you want to use.
gEDA is an open source package that runs on Linux, Unix, Mac, and very limited Windows functionality. It includes schematic capture, attribute management, bill of materials (BOM) generation, net listing into over 20 netlist formats, analog and digital simulation, gerber file viewer, Verilog simulation, transmission line analysis, and printed circuit board (PCB) design layout. Gerber outputs are supported.
DesignSpark PCB is a free EDA package offered by RS Components. It has a board size limit or 1 sq meter or 1550 sq inches and no limits on pin counts, layers, or output types. DesignSpark PCB includes schematic capture, PCB layout, autorouting, circuit simulation, design calculators, BOM tracking, component creation wizard, and 3d viewing. Eagle component libraries, design files, and circuit diagrams can be imported in to DesignSpark PCB. With the extensive library of Eagle components available online for free, the ability to import component library files makes transitioning and starting in DesignSpark PCB fast and easy. DesignSpark PCB outputs all of the required files to have you PCB made at any PCB manufacturer.