Qualcomm will first minimize its risk going into the PC market by making its mobile chips a bit more optimized for the PC market. But if that goes well and all, it may eventually go "upmarket" with higher-end chips, which will require their own R&D and so on.
However, I don't know if that necessarily means we'll have a more open alternative to Intel. Evidence so far seems to show that Qualcomm may be an even bigger bully than Intel was or is, so I would not look up to Qualcomm to being a savior for the market, but more like the tyrant that replaces the previous tyrant.