I just discovered today that gdb runs fine within the pbterm application. So, if you can use pbterm as your commandline interface, then you don't need to do remote debugging via gdb.
You need to install gdb, libncurses.so.5 and libreadline.so.5 from the debian lenny armel distribution. Install gdb to /mnt/ext1/system/bin. Install the two libraries to /mnt/ext1/system/lib. Then within pbterm on the device:
export LD_LIBRARY_PATH=/mnt/ext1/system/lib
export PATH=/mnt/ext1/system/bin:$PATH
gdb <program-path>
You can use the multi-task menu on the device to switch between pbterm and the application if necessary.
I've provided the gdb binary and the two libraries that I copied from the debian lenny armel distribution as an attachment. Sources for those are available in the debian archives.