> I already tried
>
> SELECT * FROM mytab WHERE myblobfield LIKE '%longstreet%'
>
> but didn't work as expected (I'm using PHP + FB1.5, and WIN1251).
> But now I see that CONTAINING is better because of it's case
> insensitivity.

Unfortunately collation can't be specified for blob fields,
which means CONTAINING is case sensitive for non-ascii
(i.e. national) characters.
You would have to store the contents uppercased,
or use UDF for fully case-insensitive search,
or use VARCHAR as you proposed.

Ivan