The Collaborative International Dictionary of English v.0.48:

Omnipresence \Om`ni*pres"ence\ ([o^]m`n[i^]*pr[e^]z"ens), n.
   [Cf. F. omnipr['e]sence.]
   Presence in every place at the same time; unbounded or
   universal presence; ubiquity.
   [1913 Webster]

         His omnipresence fills
         Land, sea, and air, and every kind that lives.
                                                  --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

omnipresence
    n 1: the state of being everywhere at once (or seeming to be
         everywhere at once) [syn: ubiquity, ubiquitousness,
         omnipresence]