Shaad

Firstly update your rom to PR 1.2 if its not alreday on the latest version. This will make your device much faster in general.

Secondly install Faster Application Manager from the pre-installed Application Manager. as the name suggests this is much faster than the normal app manager in installing and uninstalling apps from the different repositories.

also from the N900 browser fo to the OVI store (which is preinstalled as an icon) and you will get more apps from there.