vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.
Clio - Clio provides a full suite of web-based practice management tools targeted specifically at the administrative needs of sole practitioners and small firms.
Freeplane - Freeplane is a powerful and free software for building mind maps.
MyCase - Practice More, Manage Less.
Pencil Project - Single-user mockup / wireframing / diagramming tool
PracticePanther - PracticePanther offers CRM, invoicing, time tracking and communication solutions for law firms.