A Relevant Question
As a complement to the excellent answers above, I would also ask:
Do you really want to learn to use Beamer?
The package has a learning curve - perhaps more than any other slide package for LaTeX - so it's worth checking the pros and cons. For me these are...
- Almost everybody seems to use it (but does everyone share their source with you? If not, then visual conformity is the only advantage)
- Signals that you know LaTeX and will probably have math in your slides, which may have some cachet. [This is not meant ironically; sometimes it is helpful]
- It's easy to make an article into a talk and vice versa by cut and pasting.
- You fit a very large amount of text and math on a slide with the defaults.
- Code snippets can be awkward to escape properly.
- The built in styles almost all encourage large amounts of boilerplate visuals: sequence in slide set, etc.
Things you could argue either way:
- There is a pause command for building up slides line by line (Do you like this? I don't)
- Templates are difficult to change so you mostly end up with the built-in ones
For these reasons I've always decided against. For me, visually more pleasing and much simpler options include Foiltex or [gasp] LaTeX's own built in slides class.
Relevance to the Original Question
The relevance of these considerations to the original question is the following: With the tools mentioned above, once one knows how to write the most basic latex document and include pictures in it, there is nothing more to know to be able to make slides.
Not only does this leaves more time for debugging Sweave, which you'll do a lot of, but also frees up time to figure out things like xtable, apsrtable and/or the mtable function in memisc that will turn R model objects to nice LaTeX. These are all worth figuring out before wrestling with a slides package because they are more generally useful.