Don't know what stage of the game you're in. If you had not purchased the SSD yet, you may want to hold it off. Your Dell was made in 2008 so it is pretty much aged. Even if it will run for another couple of years, it is quite slow. I had a Vostro 1500 of the same era. It was getting to be intolerably slow and I got rid of it.
In any case, if you're going to get a new SSD, you may want to cough up a little more to get at lease a 256Gb, if not 500 Gb. They had come down quite a bit on price and a 256Gb can be had for less than $100.
I upgraded my relatively new Toshiba i7 laptop with a 256Gb SSD about year or year and half ago. I absolutely love it. My laptop has no moving part and it is quiet and fast. The fan never came on. Boot time is under 30 seconds, but I don't shut it down too often. Huge programs like Photoshop and Visual Studio was loaded almost instantaneously. I only wish I had put in a 500+ Gb, but then $$ was a lot more 15 months ago.
The easier way to switch over is to image the drive. You can do that as long as your old drive contains less "used" space than the SSD. Most of the SSD supplies you with the software to do that. I use Macrium (the freebie version) and I would highly recommend it because it is not brand-specific. It would be a bit confusing to learn how to use it. But it is very good after you master it. In there, you can allocate and resize the SSD partition to make it possible to change over from a larger HD to a smaller SSD. I did mine a a couple more for my friends so I am extremely comfortable with the process.
For me, this is almost the best upgrade I had had since PC came along.
Good luck. If you have any more questions about porting your drive, feel free to email me or ask it here. I'll be glad to help.