go to :
start->programs->Microsoft sql server 2008 or 2005->business intelligence development studio
create new project
from left panel select business intelligence, in right panel select Integration Service project
then your new project will create
a file with .dtsx extension will create automatically, this is an SSIS PACKAGE
you redirected to ssis package designed automatically
there are some tabs there,
first one is CONTROL FLOW
and second is DATA FLOW
you should add your tasks there in control flow.
for example in your case you should add a DATA FLOW TASK inside control flow
then double click on it, you will redirected to data flow tab
in this tab,
add a OLE DB SOURCE, and set it to your database table which you want to export data from it
add a FLAT FILE DESTINATION, connect green arrow after oledb source to this destination, and then set destination to text file you want to export data to this .
this was a simple walkthrough to Data Flow in ssis
let me know if you have problems in implementations