This is an excellent applet for experimenting with and learning about different search algorithms. It has several uninformed and informed search algorithms and example graphs to run them on, and includes a small tutorial. Note that their description of lowest cost search (i.e. uniform-cost search) in their tutorial appears to be wrong: it should say "start node to the frontier node" rather than "start node to the goal node". Best-first search and A* search are two informed search algorithms that we will talk about next week.
Search applet from AISpace project