managed vs unmanaged switches

We are using a 24 port hub (still working well) 3-com Linkbuilder, but thniking of upgrading it to a new 24 port swicth to get to Fast Ethernet. I am no expert so, what is the difference between a ‘managed’ and an ‘unmanaged’ switch. Is it that a managed switch has software that comes with it you put on one of the servers to ‘control’ some of the wicthes functional capabilities, while an ‘unmanaged’ swithc is ‘dumb’ in the sense it does what it does (per it’s specs) and that’s it, no administartive control?
Also, in the catalogs we sonstantly get it mentions ‘standalone’ switches, what does that mean?
Thanks