Poland
Decide Tm for your amplicon before running a HRM assay.

Primer3
Tool for web-based primer design

Netprimer
Tool for analyzing primers for Tm, secondary structures and primerdimer formation

BLAST
Tool for sequence search in databases

Ensembl
Annotation of several eukaryotic genomes

mFold
Tool for checking secondary structures of DNA or RNA

Oligonucleotide Properties Calculator
Tool for establishing the physical and chemical properties of oligonucleotides

Ambion DNA/RNA Concentration Conversion Calculator
Convert between different concentration units

DNA/RNA Absorption Concentration Calculator
Tool for converting measured absorption to concentration of DNA or RNA in your sample

RTPrimerDB- primer and probe database
Database of predesigned QPCR primers and probes

Real-time PCR primer and probe sets
Database of predesigned QPCR primers and probes

Exon Primer
Tool for designing exon-spanning primers

Java Molecular Biology Lab
A variety of molecular biology tools