I remember thread about some battery powered equipment which called for 5V
regulator with lowest possible qiescent current. In the last issue of EDP I
have found the MIC5230 by MICREL:

5V @ 10 mA
1uA quiescent current
Low dropout (13 mV @ 1 mA)
3% accuracy
5pin SOT23 package

Does not require output capacitor (but the PIC will certainly need one).

Their other power management products are also worth checking - micropower
charge pump with no external capacitors, LDO regulator with undervoltage
detector, P-chanel high side swith, all in SOT 23 package.

Internet info:
http://www.micrel.com
mailto:info@micrel.com.uk

Regards

Josef Hanzal