READSEQ will read in formatted sequence files and convert the sequence information in the files into another file that has a different format. Readseq is particularly useful as it automatically detects many sequence formats, and interconverts among them.

Formats which readseq understands:
  IG/Stanford, used by Intelligenetics and others
  GenBank/GB, genbank flatfile format
  NBRF format
  EMBL, EMBL flatfile format
  GCG, single sequence format of GCG software
  DNAStrider, for common Mac program
  Fitch format, limited use
  Pearson/Fasta, a common format used by Fasta programs and others
  Zuker format, limited use. Input only.
  Olsen, format printed by Olsen VMS sequence editor. Input only.
  Phylip3.2, sequential format for Phylip programs
  Phylip, interleaved format for Phylip programs (v3.3, v3.4)
  Plain/Raw, sequence data only (no name, document, numbering)
  MSF multi sequence format used by GCG software
  PAUP’s multiple sequence (NEXUS) format
  PIR/CODATA format used by PIR
  ASN.1 format used by NCBI
  etc.
  Pretty print with various options for nice looking output. Output only.

You can use readseq online :
  in Lille
  at Pasteur Paris