Hi,
Welcome to the forum.
When you have Lightroom 2 today, then I think you should upgrade to Lightroom 3.
You do not write which Pentax you have bought, but you will probably be able to shoot RAW DNG instead of PEF. If you do, you can open the RAW files in LR2 as well.
Nevertheless, I would still upgrade to LR3 because this version do an amazing job regarding noise handling etc. You can shoot at higher ISO and still get a almost noiseless result with LR3 compared to LR2.
Welcome to the forum.
When you have Lightroom 2 today, then I think you should upgrade to Lightroom 3.
You do not write which Pentax you have bought, but you will probably be able to shoot RAW DNG instead of PEF. If you do, you can open the RAW files in LR2 as well.
Nevertheless, I would still upgrade to LR3 because this version do an amazing job regarding noise handling etc. You can shoot at higher ISO and still get a almost noiseless result with LR3 compared to LR2.