There is a very interesting newsletter I am subscribing to, namely the Methods and Tools one.
Methods & Tools is a free magazine with PDF and text issues with practical knowledge, information and resources on software development and software engineering: UML, Agile Methodologies (eXtreme Programming - XP, Scrum, Test Driven,..), Software Testing, Configuration Management, Databases, RUP, Software Project Management, Programming (Java, .NET, Ruby on Rails, Ajax), Software Analysis and Design, Quality Assurance, Software Process Improvement (CMMI), Software Development Tools, Risk Management, etc.
Past issues are available as PDF or text.
