The level is 48. It used to be 49 back when pure casters only got spells every 4 levels to level 24, then every 5 levels thereafter to 49, but when they changed it to where you get spells every level, this spell's level became 48.
I'm new to the research thing and find it hard to find all the words for research and I'm running out of PP because people in the baz want to sell the words so high where can I find the words from lvl 16 to 30 to make my spells.
Allakhazam's is excellent for helping you find the places where the words you need drop. Just enter the name of the words you need in the "Item Lookup.." section and it will direct you to the mobs and zones you need to go to. Occasionally there will be listings that haven't been updated in a while, so be sure to look at the forum postings following the item descriptions for update info from players.
If i'm reading the info right, it says you need 2 Words of the Ethereal, last I checked and last time I did the combines for this spell (which was quite often to skill up research) you only needed ONE copy of words of the ethereal per combine, not 2 as stated above.
Perhaps for some dumb unknown reason this was changed, but if its still the same, only 1, not 2.