simple. Use a cloning program like acronis or migrate easy to clone your old data to the new drive - unless you want to a clean install. (your choice.) This is easy, and will work fine if going from IDE to IDE, or SATA to SATA. Ensure you let the cloning program finish completely or you'll end up with TWO corrupted disks that you will have to format and you will lose all data.
I however, recommend going with a fresh install and just copy the data you need from the old drive. If doing a fresh install, just remove the old drive, replace it with the new drive and install your OS with all the programs you need. Keep your old drive as a secondary backup device or use it for additional storage (or both) !
If you are switching types of drives like IDE to SATA, you will need to have your SATA drivers handy and you will need to do a fresh install. You cannot clone as your OS will not have the SATA drivers on the cloned drive and it will not boot. Have your SATA drivers on a floppy drive handy when XP tells you to install the drivers. You will need to put the disk in with the drivers and hit F6.
If you have another type of OS, follow the prompts.