invisibility detection

[spellhurler]

ok im new to 3rd ed. (dragged kicking and screaming from 2nd).
Is there a roll of somekind to detect the presence of an invisible creature?
used to be reserved for lv 12 and up to get an int check i think.

 

[Infiniti2000]

A spot check of DC 20 gives someone a "hunch that something's there." You can even pinpoint an invisible creature with a spot check, but it's very hard. You can also use listen checks and special abilities like scent, blindsense, spells, etc. For starters, go here:

http://www.d20srd.org/srd/specialAbilities.htm#invisibility

 

[Arkhandus]

The DC is higher, IIRC, if the invisible creature is not moving.

Also, you can hear stuff walking past you or the like, on a stone or wooden floor for example. Through the Listen skill. Invisibility does nothing to mask your sounds, only your appearance. If you make a Listen check you can probably tell roughly which space an invisible creature is situated in, as long as they're making enough noise for that to be pinpointed, and close enough for you to figure it out.