Resolution / Printing Help

I have a digital rebel xt and in the past took pictures as large JPEG which have a resolution of 72. I now think I understand that for printing the photo's should be at 240-300 DPI (resolution).
1. Does this mean i should resave all my photos that I am going to print at 300 DPI?
2. I also would like to know if you save a copy at say 72 DPI and also at 300 DPI for printing?

3. It seems saving two copies is a little much and I would think saving at the higher resolution would be the thing to do?

4. I also noticed that in Raw my camera shoots at 240 DPI is this ok for a nice print.

5. Any special things I should do before croping the JPEGs I have that are 72 DPI?

Thanks Joe

IMO and this is what I end up doing you need to have a workflow with the output resolution in mind so for web images I leave the dpi at 72 because dpi is irrelevent for screen output/showing but for printing I use 300dpi where possible and this info here courtesy of the good folk over at dpchallenge may help http://www.dpcprints.c​om/help.php?faq_id=61 with understanding the minimum an maximum resolution with dpi for a given print size.

HTH