Need help exporting tables to text files

I am fairly new to Oracle and have been asked to export some tables to a text file. I've come up with the following solution:

Using SQL*Net, Log on with appropriate name and password. Set the Column Separator to "|" (chosen because fields will not contain this character)
Set the Spool to file "oraTable.txt"
run the SQL command - SELECT * from <table>? Set spool to off
and return Column Separator to ""

I cannot see any problems with the above however, I have a few concerns.

If a field in the table contains a null value will it export to file or will it be skipped?
When I run the SQL command, the column headings appear everytime the screen is filled.
How can I switch this off (or better still, have the column headings at the beginning)
How can I switch the word wrap off? SQL*Net exports the table with the word wrap also.
How can I list all of the tables within the database along with the table size and table owner?

Thanks In Advance Received on Tue Jan 11 2000 - 02:51:07 CST