This script scrolls the given text in the third line, one drawback is, that it counts as a typing, so it’s not possible to scroll and to chat. But, it’s a good message poster. You can set the delay with the delay 0.09 line.
OS version: OS X
---------- script start ----------
-- idea and script: spoun@mac.com
set a to every character in ":) ;) :( :/ :O :D :* :P :[ 8) >:O O:) :'( :X :$ "
set h to ""
set i to 1
set c to count every item in a
repeat
repeat with n from 1 to c
repeat with m from 1 to c
set h to h & item i of a
if (n = 1 or n mod c = 1) and i = (c) then
set i to i - (c - 2)
else if i = (c) then
set i to i - (c - 1)
else if m = c then
set i to i + 2
else
set i to i + 1
end if
end repeat
tell application "iChat"
delay 0.09
set status message to h & ""
set h to ""
end tell
end repeat
set i to 1
end repeat
---------- script end ----------