I tried several security software programs and didn't really like any of them. Either they required a text password (too cumbersome) or they didn't work after a soft reset, or they just offered too much (encryption, etc.) and/or were too expensive.

I prefer a graphical interface like gridlock but that software always crashed my 270. I found one that is simple and works perfectly for me and isn't very expensive. It's called Visual key http://www.viskey.com/viskeypalm It works by displaying a picture and you click on points in a user-specified order. There was another software that worked the same way on palmgear but it didn't work after a soft reset on GPRS enabled Treos. This was because the GPRS patch disabled the security application. I don't know why they did this but they did. Even emailed HS and they told me to look at 3rd party apps! Visual key works after a soft reset. I plan on purchasing this software. It even has a free windows software that allows you to create a custom picture as your entry screen. Very cool.

I don't have any affiliation with the company - just a very satisfied user after a long search.