Looking at the specs it looks like the android version on it is 2.1 which is eclair, in all reality the lowest version you should actually want to use to get the most out of would be a minimum of 2.2 froyo. Are you looking at purchasing one of these, cause frankly it is a bit outdated. Also, what kind of smart phone user are you (new to smart phones, hardcore user, or just making phone calls and checking email?)
I say you want 2.2 at a minimum because 2.2 became an unofficial standard in the android market. Most devices with 2.2 on them can run the majority of apps, but unfortunately there are quite a few of the newer and more useful apps that simply won't work with 2.1, so if you're looking for an android phone to play around with apps, it would be worth it to get one with 2.2 or preferably 2.3 gingerbread.
To give you a little more info as well, only 11% of all active android devices are running 2.1. 45.3% are running 2.2, and 38.7% are running 2.3 so you would essentially be shooting yourself in the foot for phone feature upgrades and functions.