i do have a question though... if i were to upgrade the OS(eclipse?), do i need to remove everything or the OS can be upgraded easily? i read that the only stable one for the phone is FP1 ( i would love ICS...)
1. Eclipse is a ROM, not an OS. It is based upon Samsung's FP1 build of Android 2.3.6 as of Eclipse 2.0.
2. If you're upgrading from one version of a ROM to another version of the same ROM (ie. Eclipse 2.0 -> Eclipse 2.1, when it comes out), you can usually do so by flashing the update over your current setup. If you're changing ROMs (ie. Stock -> Eclipse, Stock -> Tweaked, Eclipse -> Tweaked, etc), then you should do a complete wipe of your phone (data, cache, and dalvik cache). You can then restore user apps and user app data (never system apps, system app data, or settings) from Titanium Backup.
3. There is no ICS for the Droid Charge... at least not one that is fully working. Samsung has not released the code for the phone's RIL (radio interface layer), so devs have been mostly unable to get an ICS setup to fully work with 3G/4G. There is an ICS release that is wifi only (or perhaps some 3G at this point) floating around, though it's far from a daily driver.