The Collaborative International Dictionary of English v.0.48:

forthcoming \forth"com`ing\ (f[=o]rth"k[u^]m`[i^]ng or
   f[=o]rth`k[u^]m"[i^]ng), a.
   1. Ready or about to appear; making appearance.
      [1913 Webster]

   2. Candid; frank; not withholding relevant information;
      cooperative in providing information.
      [PJC]

   3. Having an agreeable and sociable personality; friendly.
      [PJC]

   4. Available or ready at the time required; as, payment will
      be forthcoming on receipt of the goods.
      [PJC]

WordNet (r) 3.0 (2006):

forthcoming
    adj 1: at ease in talking to others [syn: extroverted,
           forthcoming, outgoing]
    2: of the relatively near future; "the approaching election";
       "this coming Thursday"; "the forthcoming holidays"; "the
       upcoming spring fashions" [syn: approaching, coming(a),
       forthcoming, upcoming]
    3: available when required or as promised; "federal funds were
       not forthcoming"

Moby Thesaurus II by Grady Ward, 1.0:

174 Moby Thesaurus words for "forthcoming":
   about to be, access, accessible, accession, advance, advancing,
   advent, affable, afflux, affluxion, already in sight, amiable,
   anticipated, apparition, appearance, appearing, approach,
   approaching, appropinquation, approximate, approximation,
   approximative, appulse, arising, at hand, attracted to, avatar,
   awaited, brewing, chatty, close, close at hand, close by, coming,
   coming into being, coming near, coming toward, coming-forth,
   communicative, departure, desired, destinal, destined, determined,
   disclosure, drawn to, egress, egression, emanating, emanative,
   emanent, emergence, emergent, emerging, epiphany, eventual, exit,
   exodus, expansive, expected, exposure, extraction, extrapolated,
   fatal, fated, fatidic, flowing toward, foreseen, free, friendly,
   future, futuristic, futurity, gathering, going on, going out,
   going to happen, hereafter, hoped-for, immediate, immediate future,
   imminence, imminent, impendence, impendency, impendent, impending,
   in danger imminent, in embryo, in hand, in preparation, in process,
   in production, in progress, in prospect, in reserve, in store,
   in the cards, in the offing, in the oven, in the wind,
   in the works, in view, incarnation, informative, instant, issuance,
   issuing, later, loom, looming, lowering, lurking, manifestation,
   materialization, materializing, menacing, near, near at hand,
   near future, nearing, nearness, occurrence, on stream,
   on the anvil, on the fire, on the horizon, on the way, oncoming,
   open, opening, outcome, outcoming, outgo, outgoing, overhanging,
   pending, planned, plotted, predicted, preparing, presentation,
   probable, projected, prophesied, prospective, proximate,
   proximation, realization, revealing, revelation, rise, rising,
   showing, showing forth, sociable, surfacing, talkative,
   that will be, theophany, threatening, to come, to-be, transeunt,
   transient, ultimate, under construction, under revision, under way,
   unfolding, unfoldment, unreserved, upcoming, waiting