My Summary of events based on this thread: (for anyone who still doesnt have a clue what is going on).
We have debt. A lot of debt. This was brought on us - as we all know - by the Glazers, who stupidly decided to take out PIK (Payment In Kind) loans to finance their takeover. PIK's are essentially just loans, but with far higher rates of interest specifically, our ones are at 8% and 14.25%, which is the main cause of our problems as we cannot afford to keep up with the interest payments. Because of that, the interest is getting "rolled up" into the debt, and it builds up like a rolling snowball or downward spiral, whichever you prefer.
When the PIKs are due to be repaid, if the Glazers cannot stump up the cash, the value of the loans will be given to the investors in shares for whatever the Glazers cannot/have not paid.
Now, bonds are essentially just another type of investment or loan, a lot depends on the exact terms and structure of the bonds, but from what we have heard, chances are that we are going to issue bonds for £600m - giving us the money to pay off the PIKs. The bonds would be repayable in about 2017 (again, depends on the terms and conditions) with a rate of interest of about 5% - far lower than the PIKs - which is normally paid on an annual basis. So in 2017 we will need to pay off £600m, but until then we will have far lower interest payments, which all in all is probably a good thing.
The real question remains however, how they plan to pay off the money on a bond in 2017 other than by selling the club. Because whilst the PIKs will simply be converted to equity (shares) if they cannot be paid - the bonds will likely have no such clause in them, and will need to be paid back in cold hard cash, something that is in short supply at the moment for us.
I think that roughly sums it up (based on my fairly poor financial knowledge).