Well, seing as you don't know what skinning is I'll asume you MSN Messenger isn't skinned
. What version are you using?
[offtopic] Skinning is a way of changing the way you MSN Messenger client looks. You can change the hole theme and look of your MSN Messenger and all the icons. There are many out for MSN Messenger 7 and are simply downloaded and you install it. Skins are
illegal though and some may also be untrustworthy and corrupt you MSN Messenger or have viruses attached.