Oligo calculator - (Aug/05/2003 )

I am seeking good oligo calculators online that check for Tm, GC% and importantly secondary structures of the oligo.
Thanks.
Serge.

Check IDT's Oligo Analyzer program at www.idtdna.com. Go to customer service and then Oligo Analyzer. Program gives Tm, %GC, e260, structures, self-dimerization and dimerization with another primer.