Faraday touch switch or more commonly known as "Capacitance Touch Switch" are very common circuits and are easy to implement. They don't require any special touch pad hardware or even specialised controller chips.

http://www.discovercircuits.com/C/capacitance-sw.htm

Also google "Capacitance Touch Switch" or "Faraday touch switch" for much, much more information and plenty of easy-to-build circuits.

As for the step-up 2.3V to 3.5V DC power supply (also called boost converters), this is also easy as they are common now days and many are specially designed for 2x1.5V (Alkaline,) or 2x1.2V (NiCAD, Ni MH, etc) batteries. Numerous microchip manufacturers make these and they are readily available from local suppliers such as Farnell, RS components, Digikey, etc.

http://www.linear.com/pc/viewCategory.jsp?navId=H0,C1,C1003

http://www.national.com/analog/power

http://www.onsemi.com/PowerSolutions/home.do

etc.

Due to the nature of the touch switch you can use it as a simple switch element to control your microprocessor and associated flash memory chip. There are special chips on the market (called voice record chip or similar) that will do the job with a minimum external part count (the microprocessor, memory chip and many of the associated electronics are all located within the chip).

eg....

http://www.aplusinc.com.tw/pro-ivr.html

also try an internet search of "voice or message record chip" or similar for message chips and easy-to-build circuits. Also many other microchip manufacturers make these and they are available from local suppliers such as Farnell, RS components, Digikey, etc. All but the simplest message chips should have the ability to pause a message.