A web cam........
And of course!!
You can use any make of the hardware or software but the software i have shown you is free!
Download Helium frog and install it.
When you open the program it should find your web cam and off you go...
Press the space bar to take a picture then move you Lego and take another picture
keep going till you have finished you film.
Close the program when finished and open up you editing program
Go and find the film you have shot,It should be in helium frog captured frames
Then edit away add Titles, sound and any effects.
Render the film and upload to Youtube!
Simple as that!!!
A few helpful links
If you have a Apple Mac... Sorry, But the top links should help.
A good place for sounds is