AVR-Chat

My recommendation is to get a STK500.  They're about $80 at DigiKey 
(http://dkc3.digikey.com/PDF/T042/0294.pdf).  It supports a wide 
variety of chips and serves as a simple test bed (lights, switches, 
etc.).  Its ISP programmer can also be used to program your AVR in 
its circuit simply by connecting a 6-conductor cable between the 
STK500 and your board.

Another option is to build a simple serial programmer.  I have built 
one that uses an AT90S2313 and supports the AVR-910 protocol.  Some 
examples of this type may be found here:

http://www.serasidis.gr/circuits/avr_isp/avr_isp.htm
http://www.peg.si/electro/avrprog.html


I built the one using the 2313 and it works well.  However, the 910 
protocol is slower (perhaps 5x) than that used by the STK500 so if 
you're planning to program the larger devices this may be an issue.

The parallel interface is perhaps the simplest.  I have not built one 
but I have read a lot about them.  The software most often mentioned 
is PonyProg.  You can read about it and see the interface schematic 
here:

http://www.lancos.com/prog.html