I like to keep organized and efficient. And keeping track of your EV Training by tallying or making a spreadsheet isn't really quick, and often leads to errors (losing track, forgetting a battle). So, I designed the Pokemon EV Counter program using Game Maker. This program let's you set up a team of up to 6 Pokemon and plan what you wish to EV Train them in, and then let's you count how many EVs your Pokemon get for each stat. You can even save and load so you don't have to worry about losing any data. It won't let you go past 255 in one stat or 510 total, so it's hard to actually make a mistake (and even if you do, you can subtract EVs).
I've already used the program once for EV Training one of my Pokemon and it made everything so simple. However, I think the best part of the whole program is the very detailed EV Guide I made (which you can open anytime by pushing F1). This guide tells you everything you need to know about EVs and even shows the best places to EV Train (in Diamond/Pearl/Platinum).
If you want a simple way to EV Train your Pokemon, then I highly recommend you going to my site and downloading the Pokemon EV Counter. Here is the link to my site:
http://www.aa5tb.com/cody/PokemonEVCounter.html
Please let me know what you think of the program and any suggestions you may have for it. =)
I do regret to say that this program only works for Windows, sorry Mac and Linux users... =(