steel needles are available from many suppliers, some listed below.
HOWEVER - if you are planning to transfer 78's, and/or are concerned about preserving them, I suggest using a modern cartridge fitted with a diamond stylus of the appropriate dimensions - depending on the age and condition of the recording.
Thomas.

http://www.thoseoldrecords.com/recsup.html

http://www.78rpm.com/merchant2/merchant.mvc?Screen=CTGY&Store_Code=NRC&Category_Code=112

http://www.garage-a-records.com/products.php?cat=161