There are four great communities that I would like to mention briefly regarding project management as a whole. These communities have a range of useful meetings, presentations, training options and their own certifications. You might already be familiar with them, here we go:
Project Management Institute (http://www.pmi.org/)
Known best for its PMP certification, which could be described as the Holy Grail in project management certifications. A person that has this certification has an extensive knowledge on project management theory and practice. PMI does regular conferences with great key note speakers, and has a great community with active members providing valuable Project Management information.
International Project Management Association (http://ipma.ch/)
IPMA is a Federation of 50+ Member Associations (MAs). The MAs develop project management competencies in their geographic areas of influence, interacting with thousands of practitioners and developing relationships with corporations, government agencies, universities and colleges, as well as training organizations and consulting companies.
Microsoft Project User Group! Yeah I love easy acronyms that describe the community best as possible. The site features some of the best blogposts from the greatest minds in the business. And I am very very proud to say that even some of my own posts have been featured on the site. Become a subscriber to the newsletter, every newsletter comes with a new interesting post.
Ik doe projecten (www.ikdoeprojecten.nl)
If you are in The Netherlands this is a great site to get into the community for Project Management. I started my writing for websites here, but am not active on the site anymore.