List all database containing table and value
I'm guessing on the first column - replace ColumnName below with the actual column name. Also it's always useful to specify which version of SQL Server you are using - I've assumed 2005.

DECLARE @DBType CHAR(1);
SET @DBType = 'A'; -- or 'B';

DECLARE @sql NVARCHAR(MAX);
SET @sql = N'';

CREATE TABLE #x(DB SYSNAME);

SELECT @sql = @sql + 'IF EXISTS (SELECT 1 FROM '
  + QUOTENAME(name) + '.sys.tables WHERE name = ''DBType'')
  INSERT #x SELECT ''' + name + '''
    FROM ' + QUOTENAME(name) + '.dbo.DBType
    WHERE ColumnName = ''' + @DBType + ''';'
FROM sys.databases;

EXEC sp_executesql @sql;

SELECT DB FROM #x;

DROP TABLE #x;