Lets also take a look at 4e PHB p23:
Evil and Chaotic Evil Deities
Your character can worship an evil or a chaotic evil
deity without being of the same alignment, but that’s
walking a fine line. The commandments of these
deities exhort their followers to pursue evil ends or
commit destructive deeds.
So worship of those deities is not against the rules either.
PHB p62
You must choose a deity compatible with your alignment:
Good clerics serve good deities, lawful good
clerics serve lawful good deities, and so on. If a deity
is unaligned, your alignment doesn’t matter, so a deity
such as Melora has good, lawful good, evil, chaotic evil,
and unaligned clerics in her service. Similarly, if you’re
unaligned, you can serve any god. For example, Pelor is
served by both good clerics and unaligned clerics, but
never by evil, chaotic evil, or lawful good clerics.
For most games, you should choose a good, lawful
good, or unaligned deity for your cleric. Ask your
Dungeon Master before you select an evil or chaotic
evil deity.
Not against the rules for clerics either, just the caveat that you ask your DM first.