Introductions:

Good Introduction: "Invitation to the Septuagint" by Jobes and Silva

Septuagint Text:

Rahlfs version (no English)

Brenton version (parallel English)

Concordances:

Hatch and Redpath, "A Concordance To The Septuagint"

Lexicons:

Taylor, "Analytical Lexicon To The Septuagint"

Grammars:

Conybeare & Stock, "Grammar of Septuagint Greek"