Looking at the D20 SRD Summon Monster 1 list, I see "Celestial Owl" and "Celestial Dog" (both LG). Two questions: could Milo summon a Celestial Owl and have it deliver letters for him, akin to a HP owl? (I doubt he *would*, since that'd be a dreadful waste

1) He couldn’t have it deliver a letter, because the duration that a summoned creature exists is only 6 seconds times his level—just under a minute, in this case, which is hardly sufficient to fly anywhere at all. Also, his summoned owls wouldn’t have the curious ability that HP owls have to locate the recipients of their letters. (Seriously, how does Hedwig keep finding Sirius in hiding?). There’s a spell, Animal Messenger, that does almost exactly what the HP owls do, but it’s not available to wizards without hijinks.

2) He *could* do so, I think. Most things are possible in 3.5, but off the top of my head, I’m not sure how he would. Actually, literally as I typed this I figured a way: he could make a constant-effect magic item of Summon Monster I for 1(1st level spell) * 1(caster level)*4(duration measured in rounds) *2000 (constant effect)=8000gp.

However, if that was his goal, he wouldn’t really need to do that. He’s the only one in the universe who understands how his magic really works, so he could just say that having a giant black dog following you around is normal for Wizards like him, much in the same way that having a super-intelligent rat is.