Software/Webapp for creating computer science diagrams

Question

What are some good programs or web-based applications that can be used (preferably, but not necessarily, for free) to create diagrams for computer science articles or dissertations?

Particularly, I'm looking to represent data structures such as stacks, linked lists, trees, etc..

Any ideas?

Answer 1

• Gliffy should work for you. Many of the student's in my class used it and it worked out great.
• Microsoft Visio: Not web based, but quite powerful
• Dia: Open source diagramming tool

Answer 2

I made zwibbler.com for this. For a formal article, turn down the "sloppiness" setting.