Steven,

> Can someone tell me the Charset & Collation to use with Firebird 1.5
> for Spanish that will either ignore accented letters or sort them
> immediately after the same letter without an accent.

You should post that to the firebird-support list.

Apart from that, I don't know how the Spanish collations work but as
there is just one Spanish collation in Firebird 1.5 there aren't many
options. (There is a new ES_ES_CI_AI case insensitive, accent
insensitive collation for Firebird 2.0 though).
See more here:
http://www.destructor.de/firebird/charsets.htm

Regards

Stefan