SELECT entradas.* , (SUM(v1.puntuacion) - SUM(v0.puntuacion)) AS total_likes
FROM entradas
LEFT JOIN valoraciones v1 ON v1.entradas_id = entradas.id and v1.puntuacion=1
LEFT JOIN valoraciones v0 ON v0.entradas_id = entradas.id and v0.puntuacion=0
WHERE fecha >= :fecha1 AND aceptada=1
GROUP BY entradas.id
ORDER BY `total_likes` DESC
limit 5
[EDIT]
Sorry mate, the query abover is not quite alright. I think the right answer for what you are looking for is this one below:
SELECT entradas.* , SUM(IF(v.puntuacion = 1, 1, -1)) AS total_likes
FROM entradas
LEFT JOIN valoraciones v ON v.entradas_id = entradas.id
WHERE fecha >= :fecha1 AND aceptada=1
GROUP BY entradas.id
ORDER BY `total_likes` DESC
LIMIT 5