EDIT: This post has updated version. See the latest version: bpmtips.com/free-tools-for-business-process-analysts-2015-edition/
Below you can find list of a free BPM (Business Process Modelling)/BPA (Business Process Analysis) tools. They are divided into 2 sub-lists: one with standalone (installable) programs, and other with web-based tools.
Tools mentioned there differ much – some of them offer only very simple modelling capabilities, while others (BPA) offer also analytical mechanisms, simulation algorythms and much more. However all those tools can be used to describe business processes, understand them better and (hopefully) improve them.
If you know of other free tools for business process modelling/analysis please add them in comments. There are just two conditions: they need to be free (trials do not count), and they need to be useful for business process modeller/analyst (so even fine workflow engine does not count unless it has really cool modelling component).
UPDATE: Thanks to all of you that posted comments about BPA tools – especially to Sandy Kemsley, Rolf Hemmerling, Cathy Beauvais, Eli, Fabio Carli, Phil Webb, Bart-Jan, Jim Brown, Danielle, Gerardo Lisboa, Rojesh, John.
@ Elena – I will create a new page about BPMS tools.
ADONIS:Community Edition (www.adonis-community.com) – business process modeling (BPMN + other model types), analysis, simulation, publishing (HTML+PDF), KPI monitoring and BPMN DI import and export. See tool overview
AgilPro (available at Sourceforge) – Eclipse-based open source modelling and simulation – not reviewed yet.
Cuecent BPMN (cuecent.com) – free version available upon request by e-mail; not reviewed yet.
MID Innovator for Business Analysts (Personal Edition) (http://www.mid.de/en/products/innovator-for-business-analysts.html) – not reviewed yet
Soyatec eBPMN (www.soyatec.com) – Eclipse-based BPMN modelling – not reviewed yet.
Yaoqiang BPMN Editor (bpmn.sourceforge.net) – used to be free, but looks like commercial product now? ActiveModeler – cannot find free version Savvion Process Modeler (www.savvion.com) – BPMN modeling, simulation, and documentation. No longer available. Intalio|Designer (www.intalio.com) – BPMN modeling and BPEL Export. There’s also Intalio Server for executing processes defined in BPEL 2.0 and Intalio Workflow. No longer free. TIBCO Business Studio (www.tibco.com) – BPMN modeling and simulation. Now only 90 day trial. Update (thanks to Sandy Kemsley for info about Metastorm):
Metastorm Process Designer – Business Analyst Edition (www.metastorm.com) – BPMN modelling. No longer free. Embarcadero EA/Studio Community Edition (www.embarcadero.com) – Eclipse-based BPMN modelling. Visio import. No longer available.
Web based tools
draw.io – not reviewed yet
Gliffy – online diagramming software (www.gliffy.com). Just like Visio in your browser 😉 Still free, but with several limitations (only 5 public diagrams available)
iyopro.com – not reviewed yet
modelworld.nl – not reviewed yet, but seems to be in eternal beta
sydle.com/en/bpms/ – not reviewed yet
Lombardi Blueprint (blueprint.lombardi.com). Process documentation (with possibility to see diagram as BPMN) tool available via browser. Now IBM Blueworks Live. No longer free – only trial.