if you are talking about files/programs like music/movies/games to avoid paying for them, please see
this thread . If by "server" you mean fserves (ppl who share files with strangers) ditto and in mIRC (in any window) type
/help accepting files If you mean files that are legal to share (not violating any copyright laws) in mIRC type (in any window)
/help dcc If by server you mean a network's servers used to connect to them, thats personal choice. Be aware that many networks to not allow filesharing channels because of all the problems that has caused.