How to move system programs to sd card? System programs like youtube, gmail and maps are consuming over 50 MB of my HTC Explorer (v2.3) which is a rather low end android phone and has only 128 MB of system memory. 
As a result the low memory notification is kind of consistently visible. Can I (how) safely move them to the sd card?

EDIT: My device is rooted.
As @Cyborgz said, you have to first root the system. Take a look at this question to see your device is listed. Even if not, probably your device's closest like HTC Hero for more information.

Once rooted you have to partition your SD card to create a SD-Ext partition. See the question "SD card partitioning? Why? How?" to know how.

Then you can use apps like Link2SD to move few user applications to SD card and create link of few user applications to the sd-ext partition. By this way you would have created loads of free memory in your device. If you still want to get more like moving YouTube, GMail and Maps, you can use Link2SD to first convert them to user app (from system app) and move or link them (most likely moving will not be permitted).