I used bitcoin-iterate and gnumeric to render the current bitcoin blocksizes, and here are the results.
My First Graph: A Moment of Panic
This is block sizes up to yesterday; I’ve asked gnumeric to derive an exponential trend line from the data (in black; the red one is linear)

That trend line hits 1000000 at block 363845.5, which we’d expect in about 32 days time! This is what is freaking out so many denizens of the Bitcoin Subreddit. I also just saw a similar inaccurate [correction: misleading] graph reshared by Mike Hearn on G+ :(
But Wait A Minute
That trend line says we’re on 800k blocks today, and we’re clearly not. Let’s add a 6 hour moving average:

In fact, if we cluster into 36 blocks (ie. 6 hours worth), we can see how misleading the terrible exponential fit is:

Clearer Graphs: 1 week Moving Average
So, not time to panic just yet, though we’re clearly growing, and in unpredictable bursts.