Excel 2007 : Returning numeric characters within a field

hi joelane, welcome to the forum. your scenarios may be too unpredictable since you mentioned it's keyed by humans. i can only give you solutions based on what you provided. but it may not be applicable for the rest of your scenarios. I'm assuming 4 things:
1) the dates are either in front or at the back.
2) the slash "/" is only used for texts or dates
3) dates are always in the format of dd/mm/yyyy
4) info starts from A1

try:
=IF(FIND("/",A1)=3,TEXT(LEFT(A1,10),"ddmmyyyy"),TEXT(RIGHT(A1,10),"ddmmyyyy"))

if all years are in 2011, you can try this too:
=MID(A1,FIND("/2011",A1)-5,10)

hope it helps.

@benishiryo
Your second assumption fails on OP's first sample.

If all dates are after Jan 1, 2000 and have 2 digits for all days and months you can try:

=SUBSTITUTE(MID(A2,FIND("/20",A2)-5,10),"/","")

@cutter
ahhh my 2nd formula? you're right. forgot about the slashes