1) Too broad of question. What are you looking for? Raize and TMS are some of the best. DevExpress is one of the best as well. Depends on what sort of components you need.
2) Very easy, find a barcoder that returns ascii text. For example the Unitech USB Barcode Wand MS100U. It will read a barcode and print the barcode into any text field.
3) use google groups, all the code you want can be found there.
4) Depends how sophisticated you want. You can by a licensing component. If it is just short term you can tie it to the MAC id of your network card or something.
Use google and books as resources instead of trying to get others to do your work for you. 😉