  We report on {6,7}Li nuclear magnetic resonance measurements of the
spin-chain compound LiCu2O2 in the paramagnetic and magnetically ordered
states. Below T about 24 K the NMR lineshape presents a clear signature of
incommensurate (IC) static modulation of the local magnetic field consistent
with an IC spiral modulation of the magnetic moments. {7}Li NMR reveals strong
phason-like dynamical fluctuations extending well below 24 K. We hypothesize
that a series of phase transitions at 24.2, 22.5, and 9 K reflects a "Devil's
staircase" type behavior generic for IC systems. LDA based calculations of
exchange integrals reveal a large in-chain frustration leading to a magnetical
spiral.
