Works of Arminius, Volume 1, Disputation 4, "On the Nature of God, Paragraphs VII, XXV, and XLIX.
The Essence of God is that by which God exists; or it is the first cause of motion of the Divine Nature by which God is understood to exist.
The Life of God, which comes to be considered under the second [momentum] cause of motion in the Divine Nature, is an act flowing from the Essence of God, by which his Essence is signified to be in action within itself. (Psalm xlii. 2; Heb. iii. 12; Num. xiv. 21.)
This [i.e. the Will of God] is the second faculty in the life of God, [§ 29,] which follows the Divine understanding and is produced from it, and by which God is borne towards a known good. Towards a good, because it is an adequate object of his will. And towards a known good, because the Divine understanding is previously borne towards it as a being, not only by knowing it as it is a being, but likewise by judging it to be good. Hence the act of the understanding is to offer it as a good, to the will which is of the same nature as the understanding, or rather, which is its own offspring, that it may also discharge its office and act concerning this known good. But God does not will the evil which is called that of "culpability;" because He does not more will any good connected with this evil than He wills the good to which the malignity of sin is opposed, and which is the Divine good itself. All the precepts of God demonstrate this in the most convincing manner. (Psalm v, 4, 5.)
One may note that Arminius' views changed over time. Evidently this disputation is taken from the time when Arminius "stood for his degree of D.D." I don't quote these paragraphs to endorse what Arminius had to say, but only to illustrate the apparent difference between Arminius and some of those who are viewed as Arminians.
I would particularly ask Godismyjudge (Dan) with whom I've been having a dialog, and who considers himself an Arminian, whether he accepts the description of God's nature, essence, life, and will of God provided by Arminius, or whether he distinguishes his position from that which Arminius evidently held.
UPDATE (16 July 2008): Godismyjudge (Dan) has provided a response (link) in which he suggests at least the following:
1) That there is some doubt that the work from which these quotations come are part of the true Arminian corpus (i.e. it's possible this work was actually the work of someone other than Arminius) - Dan nevertheless concedes that Arminius probably wrote it;
2) That there is a translation issue with respect to "first cause of motion" and "second cause of motion." Dan cites Richard Mullener [sp? - transcription from Dan's audio] who argues that Arminius was trying to refer to a "first logical moment" and a "second logical moment." Sadly, I don't have access to Arminus' original Latin, in order to get into the translation issue. I don't like having to rely only on a translation, and so if anyone can point me to the original Latin, I'd be happy to dig in further.
3) Dan makes some comment about Arminius' views evolving (and some theories about why they evolved). Those theories don't particularly concern me and I was't trying to hint at them. My point was simply that there was some indication by the editor or translator of Arminius' works that suggested that this might be one of the earlier works. Given that most men's views evolve over time, I wouldn't want someone to assume that Arminius didn't have the liberty (free will, if you prefer) to change his opinions over time.
4) Dan argues that (in Arminius) the work of making a decision are done by wisdom and reason, and the will simply acts on the final judgment of reason. Dan acknowledges that this sounds like the will is determined by the reason. Dan even acknowledges that this means that freedom attaches not actually to the will itself, but to the final (or last) judgment of reason.
5) Dan recommended the 11th Public Disputation, first paragraph, to explain the connection between the reason and the will in Arminius.
6) Dan argues that the "core" of Arminianism don't include the "tangled mess" of the relation of reason and the will. Dan defines Arminianism with respect to the TULIP acrostic, such that (in his view) Arminians are those who accept T and who reject U, L, and I. Dan seems to argue that both those who accept and those who reject P are properly designated Arminians.
7) Finally, Dan states that although he'd rather not get into this level of detail (because of the danger of taking such divisions too far), he does agree with Arminius (I presume he means as modified by Mullener [sp?]).