You can do it, and people (including myself) do this - submit abstracts for still unwritten papers - regularly. There are, however, some pitfalls you should be very aware of.
1) Potential or existing collaborators
If you have collaborators, you generally want to be in agreement that results are in a state suitable for presentation, before you submit to a conference. Your presentation will not only reflect upon yourself, and your collaborators may have reservations about presenting unfinished work.
You say you are a beginning PhD student. If you already have a supervisor, it is very important that he or she agrees that the results should be presented. It could also be the case that the supervisor does not think that the results are important enough to present, in that case: listen.
2) Ethical implication: research is not fully predictable
It is quite dangerous to submit abstracts for results of research which is not carried out yet - still people sometimes do. You are often faced with having to submit an abstract maybe half a year before the conference, and you are full of confidence that the results will work out in that time. Here's the thing: Sometimes they don't. If they always did, it would not be research. I have personally seen good people been caught in this trap: Your results did not work out, but you have a pressing deadline to present these results. You could therefore be inclined to maybe fudge the results a little bit, to make them look nicer. Just always remember that this is scientific misconduct, and can never be excused. Consider if it is better not to put yourself in a situation like that.
3) Swallow your pride
You may think that these results are the most important thing the world is yet to see, or perhaps a close second. Other researchers will disagree. Since you are still pre-PhD, it is very likely that your abstract will not be accepted, because even though we would like to think otherwise, titles and affiliations matter. If your abstract is rejected, and you still have the opportunity to go: go anyway! Giving a presentation is by far not the most important thing for a fresh PhD student to do at a conference: learning, networking and asking questions are. It may also be that you are offered to do a poster presentation instead of a full presentation. If so, take it. Even though such presentations are often seen as "lesser" than talks, you will still get to discuss your research with more experienced people. This can be quite an eye-opener, and also serve as a good learning experience for giving talks later.