Если не трудно - ткни меня хотя бы в подсчёт числа дней между датами...
checkdate -- Validate a gregorian date
date -- Format a local time/date
getdate -- Get date/time information
gettimeofday -- Get current time
gmdate -- Format a GMT/UTC date/time
gmmktime -- Get UNIX timestamp for a GMT date
gmstrftime -- Format a GMT/UTC time/date according to locale settings
localtime -- Get the local time
microtime -- Return current UNIX timestamp with microseconds
mktime -- Get UNIX timestamp for a date
strftime -- Format a local time/date according to locale settings
strtotime -- Parse about any English textual datetime description into a UNIX timestamp
time -- Return current UNIX timestamp