AVR-Chat

I'm using a 741 op-amp to condition an input signal.  It's setup like a
threshold detector to detect a voltage level between .1 and .6 volts
(adjustable).  It's my understanding (and experience) that the 741 can not
operate that close to one of its rail voltages so I need to supply it with a
negative rail voltage (I'm thinking -9v).  I have 12v supplied to the rest of
the circuitry and need to avoid having a second supply (remote location).  I was
thinking that I could generate -9v using a 555 timer, caps, R's and diode to
rectify a negative voltage.  Can someone point me to a web site circuit for this
using a minimum of components?  I assume I only need a very small current.

In the short term (this weekend) I need to stick with the 741 which I have on
hand but can someone recommend an inexpensive "rail to rail" op-amp that would
be better for my final configuration which would eliminate the need for the
second supply?

Thanks in advance for any guidance you can give.  I'm mostly listening on this
list but I'm learning a lot.  Thanks to all contributors for the resource.
Someone on the list recommended "Embedded C Programming and the Atmel AVR" to
someone else.  I ordered the book and read it in short order.  I found it very
helpful in my "getting up to speed" <g>.

Regards,

Chuck Hackett