For example, Saddam apparently despises Osama, from what I’ve read. Who else that we don’t like isn’t real fond of bin Laden?
Rumsfeld?
I don’t know about “despised”, but they had completely different long term agendas. ObL primarily wants the Saudi Royal family taken down, but Saddam would have been pretty high on the list of “who’s next”. In fact, the only government friendly to Islamic theocracy in the region is Iran, but then there’s the whole Shiite thing (ObL is a Sunni). It’s quite possible that Iran and ObL could form a tatical alliance for short term gain, but it would be sorta like the Molotov-Ribbentrop Pact (both sides looking for the best opportunity to break it).
You could probably put Assad of Syria in the same category as Saddam. Not only does he run a secular country, but he’s from the (rather obscure) Alwai sect of Shi’a Islam.
One of Bush’s problems is this thinking that we must make friends with our enemy’s enemies. The premise is that there are only two types of people in the world, “those with us and those against us”. This is absurd and has gotten us into a lot of trouble over the years.
Of course he wasn’t the first to think this way. I’m sure the “politics makes strange bedfellows” logic has burned leaders since the invention of chieftains. But it is still wrong headed. There are many many combination of love, hate, tolerance, grudges, and indifference in the middle east and elsewhere in the world.
And we find ourselves trying to topple leaders that we armed a few years earlier.
Who said anything about Bush?
There’s been another popular argument, that Saddam and Osama were/are both enemies of the US, therefore they must have been friends of each other. Arrant nonsense, of course.
Who else doesn’t like either the US or bin Laden? Pretty much every other middle eastern government, afraid of being overthrown by fundamentalists and resentful of us for stirring them up.
Are the head of Hezbollah and Osama cordial? I know jack-all about the web of politics here, but I’m trying to learn. 
Unlikely. Once again there’s the Shi’a/Sunni thing going on. They’re more likely to be rivals than allies.