Sean B. Palmer
This is an attempt to collect Sappho's entire work together in one page — with Greek originals, succinct translations, and commentary.
When I first searched for Sappho's poems on the web, I found that most sites used out-of-date translations and numberings, with no original Greek. I wanted a complete work to peruse at leisure, with annotations and explanations throughout.
Whilst this page is still far from acheiving the goal of being a complete and readable edition of Sappho, it's still hopefully quite useful.
If you're new to Sappho, it's worth reading Wikipedia's introduction to her before starting on the poems. There's an awful lot of misinformation out there, so getting a good feel for the biographical and textual issues before you start on the poems will probably help you to enjoy them more.