I'm designing a course for undergrads that involves cloning and sequencing and I'm looking for a good free visual tool that will help them understand the procedure of cloning as easily as possible.
You can you can use SnapGene. It has Restriction, Gateway, Gibson and so on. Shows you all the sequences throughout the procedure step by step. You choose which sequences and enzymes(for restriction) you want to use. Helped me a lot when I was learning.
If you tell me the specific procedure that you want to use. I can see if it is possible in my copy of SnapGene and give you some basic instructions.
As Ferhat mentioned SnapGene is very simple to use and visually appealing. It does however require a licence (though not terribly expensive as Vector NTI or MacVector). If using a licenced product is not an option, ApE (http://biologylabs.utah.edu/jorgensen/wayned/ape/) can perform most of the functions you will need but it's not as pretty to look at. It is completely free to use though.
SnapGene is a great suggestion but unfortunatly this is homework, so I think ApE will have to do although I wish I could find a more graphic tool to help the students understand what they are doing