It uses two 32-bit wide memory dies for a 64-bi wide memory bus. I think it is DDR at 533 Mhz.
It isn't actually interleaving, that is the practice of sending commands to multiple chips on the same channel, as they take some time to respond. For example you can ask chip 1 for data, then ask chip 2 for data, then read from chip 1 and then read from chip 2. As opposed to ask chip 1, wait..., read from chip 1, ask chip 2, wait..., read from chip 2.
I believe there is only one chip/die per channel on these so these phones do not do interleaving.
Desktop PC's use 64-bit wide memory DIMM's, and are two to four channels wide for 128-256-bit memory busses, generally DDR 1333-2133Mhz.
Video cards, for example, have used up to 512-bit wide memory busses in the past (bost ATI and nVidia have done this).
The video card with the fastest memory bus currently is the ATI 7970, which uses a 384-bit wide GDDR5 memory bus with an effective speed of almost 6Ghz! It can transfer over 250GB/sec stock and with mild overclocks can easily do more than 300GB/sec!