The Collaborative International Dictionary of English v.0.48:

foaming \foam"ing\ adj.
   Giving off bubbles and developing a head of foam; as, a
   foaming glass of beer.

   Syn: bubbling, frothing.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Foam \Foam\ (f[=o]m), v. i. [imp. & p. p. Foamed (f[=o]md); p.
   pr. & vb. n. Foaming.] [AS. f[=ae]man. See Foam, n.]
   1. To gather foam; to froth; as, the billows foam.
      [1913 Webster]

            He foameth, and gnasheth with his teeth. --Mark ix.
                                                  18.
      [1913 Webster]

   2. To form foam, or become filled with foam; -- said of a
      steam boiler when the water is unduly agitated and frothy,
      as because of chemical action.
      [1913 Webster]

WordNet (r) 3.0 (2006):

foaming
    adj 1: emitting or filled with bubbles as from carbonation or
           fermentation; "bubbling champagne"; "foamy (or frothy)
           beer" [syn: bubbling, bubbly, foaming, foamy,
           frothy, effervescing, spumy]
    2: producing or covered with lathery sweat or saliva from
       exhaustion or disease; "the rabid animal's frothing mouth"
       [syn: foaming, foamy, frothing]