Right. Wasn’t sure if you were talking about WiFi / 3G type devices or not.
I’d probably just get a regular old pendrive and Truecrypt it, TBH. There’s plenty of password keeper type programs out there too (just make sure you have a backup of the database).
As for website passwords, how about creating a password based on the URL using an algorithm only you know? Eg, have a base password (say $fred123), then take the first three letters of the domain name (so here would be ‘sin’), put them through a ceasar cypher (one letter right would give us ‘tjo’) and then add them into the base somewhere (giving us $fredtjo123, or o$frjed1t23, or whatever).
Can be as complex as you want, gives you unique per-site passwords, and you can work out the password in your head without needing to write them all down.