PCB Manufacturers

UK

PCBs

Screenbond 1 and 2 layer, low tooling cost and cheap for standard turnrounds, can do 24hr turnaround.
Stickleback They have a prototype service via their Ebay shop
PCBTrainOnline PCBs and assembly service
PWTFull range of PCB services, including flex and aluminium
Tecbridge UK company using Chinese factories
Spirit circuits
Anglia Circuits
ABL Circuits
Cleveland Circuits
PCB Panel Flat-rate panel service
Quick-teck PCBs up to 500x630mm, online quote for instant prices

Stencils

SMT Stencil Polyester stencils
Darkmass Polyester stencils
Tecan Stainless stencils, screening cans and photochemical etching
Spark Laser Stainless stencils
PCB Train Stainless stencils
Solder Connection Stainless stencils
Order stencil together with PCBs Laser stencils from Quick-teck PCB

USA

PCBs

Advanced Circuits Full range of prototyping/production services based in Colorado; popular among university students.
Custom Circuit Boards Quick turnaround PCB manufacturer based in Phoenix, Arizona.

Stencils

Quick Stencil $99 Stencil Kit
PCB Stencils $75-$85 Stencil Kits

Canada

Bittele Electronics Prototypes PCB Fabrication & assembly; Online Calculator

Europe

Lueberg Large PCBs up to 1200x3000mm
Multi Circuit Boards Ltd. PCB prototypes and series with 1-48 layers; Online Calculator
Olimex
Eurocircuits

Poland

Techno-Service S.A. PCB prototypes and series with 1-8 layers, also in 24 hours; Online Calculator
http://zwod.technoservice.com.pl/en/SERVICEin5wd http://zwod.technoservice.com.pl/en/offered-technologies/order-prototype-special-offer-fr4-tska/,typ,fr4.html

China

http://www.exceedingelec.com
http://www.wonderfulpcb.com
http://www.pcbcart.com
single sided to multilayer, multiple board thickness, 8 or 12 day turnaround. http://www.real-pcb.com
FR4 PCB, Metal Core PCB, Flex PCB, Stencil

http://www.10pcb.com
PCB manufacturer with FR4 PCB single sided to multilayer, AL board, 1-10 layer.

Australia / New Zealand

PCBs

BEC Manufacturing

http://www.pcbzone.net/ PCBZone - Oz/NZ based panel sharing proto service.

http://www.circuitlabs.co.nz/ Circuit Labs. The commercial arm of PCBzone above. For bigger qty. Made in NZ.

http://www.acetronics.com.au/ (simple PCB's, assembly, silk screen NC mill etc)

http://www.printnetch.com.au PCB + assembly

Online - Worldwide

Techno-Service S.A. Prototypes and series from 24 hours, 5WD as a standard for series.

PCBCart Long established Chinese supplier, with wide range of options at good prices, even after shipping costs.

Eurocircuits Wide range of prototype and production services including aluminium, also stainless solderpaste stencils.

PCB-Pool Pooling service, with free stainless paste stencils.

ITead Studio Very cheap two layer prototype service.

Seeed Studio Cheap two layer prototype service with thickness and surface finish options.

DorkbotPDX Two and four layer pooling service.

PCBwing Similar to PCBcart online proto service.

PCB Main China based supplier with online quoting.

Jackaltac Online quoting. Manufacturing in South Africa but ships from Ireland. Only standard 2 layer with solder mask and top silkscreen, max. 5 units. Interesting graph of claimed competitors in FAQ page.