Hi,
Try:
#!/bin/perl -w
> use Bio::SeqIO;
>
> $in = Bio::SeqIO->new ( -file => "xp_4.ace", -format => 'ace');
> $out = Bio::SeqIO->new (-file => ">xp.phd", -format => 'phd');
> while( $seq = $in->next_seq())
> {
> $out->write_seq($seq);
> }
>
This is covered in the SeqIO HOWTO <http://www.bioperl.org/wiki/HOWTO:SeqIO>
.
Dave