There are lots of resources online (eg vanguard)
At the moment there are a few themes around the bond market
1. Interest rates paid by the safest most liquid bond instrument in the world, US Treasuries, set the market rates in US$. Over the past decades, long term interest rates have been on a long steady decline. They are near all time lows now, thanks to the crisis. As a result, long dated treasury bonds have had a long term bull market in their price. Some people think this mega-cycle has peaked, and long term bonds will slowly but surely lose value over the next decades too, especially the next one. But yields will corresponding rise, so the effect on shorter term bonds, if the trend is slow, isnt catastrophic.
2. Short term bond rates in the us are super duper low. Zero, basically. So you can borrow money easily if you are a bank. For free. All this cash is being pumped out by the Fed. to try to get everyone to spend it, and stimulate the economy. Quite artificial. So if that artificial assistance stops, rates will rise and bonds will fall in the short term. Some think the Fed would actually like more inflation, which again moves rates up.
So, what to do?
1 dont panic. Bond prices are not as predictable as you'd think. As some have mentioned elsewhere, bond funds are nicely up this year. And rates could still fall, a lot further and for some years. And if there is a big market correction in equities, they should hardly drop. So keep a % in bonds, no matter what the bond psychics portend. Minimum is usually 15% or so
2. Offset long term rate rises and inflation by getting a 4% fixed rate 30 year mortgage, and invest the capital.
3. Use laddered money market or cd certificate s for short term cash