I like this periodic table of the elements in pictures! You might pair it with this photographic periodic table, or this photo gallery of the elements from about.com. NeoK12 also has a number of videos to introduce the table and the elements. This is a catchy video introducing some of the elements as well. David's Whizzy Periodic Table helps fill in some of the gaps in knowledge from what we're learning about atoms into the periodic table, simply because you can see a "nucleus view" and a "shell view" of each element.
For older students, here's an interactive periodic table, and an interesting interactive, in association with NASA, that models the periodic table.
For those of you who would like even more links--as in, 183 links on the Periodic Table, lesson plans, and activities (including but not limited to Periodic Table Bingo and Periodic Table Tetris), click here!