Awesome, that helps a great deal. I created two blocks of Obsidian in the lava pond under my house. I then spent several minutes attempting to mine one with an iron pickaxe. That was well spent time...
As usual TheGodBen, you are a gentleman and a scholar.
Sadly not, I'm just a nerd that enables nerdy behaviour in others so that I feel less bad about my habits.
Obsidian is a pain to mine even with a diamond pick, I think it takes 8 seconds to mine one block, so you spend about a minute and a half just to mine enough to make a portal, and that's only if you're lucky enough that none of it falls into lava. You're best off mining 4 obsidian blocks, making an enchanting table, getting a diamond pick with an Efficiency enchant on it, then mining obsidian in mass quantities. It's probably faster to do it that way than mining obsidian directly.